按顺序打印字符串的所有不同字符（3种方法）-yiteyi-C++库

给定一个字符串，找到其中所有不同（或非重复）的字符。例如，如果输入字符串是“Geeks For Geeks”，那么输出应该是“For”，如果输入字符串是“Geeks quick”，那么输出应该是“GksQuiz”。不同字符的打印顺序应与它们在输入字符串中的显示顺序相同。 例如：

null

Input  : Geeks for GeeksOutput : forInput  : Hello GeeksOutput : HoGks

建议：请在“上解决” 实践 “首先，在讨论解决方案之前。

方法1（简单：O（n） ^2. )) 一个简单的解决方案是运行两个循环。从左侧开始穿越。检查每个字符是否重复。如果字符不重复，则增加非重复字符的计数。当计数变为1时，返回每个字符。

C++

                         #include <bits/stdc++.h>                       
                         using                                     namespace                                     std;                       
           
                         int                                     main()                       
                         {                       
                                                 string str =                                     "GeeksforGeeks"                                     ;                       
           
                                                 for                                     (                                     int                                     i = 0; i < str.size(); i++)                       
                                                 {                       
                                                 int                                     flag = 0;                       
                                                 for                                     (                                     int                                     j = 0; j < str.size(); j++)                       
                                                 {                       
                                                 // checking if two characters are equal                       
                                                 if                                     (str[i] == str[j] and i != j)                       
                                                 {                       
                                                 flag = 1;                       
                                                 break                                     ;                       
                                                 }                       
                                                 }                       
                                                 if                                     (flag == 0)                       
                                                 cout << str[i];                       
                                                 }                       
           
                                                 return                                     0;                       
                         }                       
           
                         // This code is contributed by umadevi9616                       

JAVA

                         import                                     java.util.*;                       
           
                         class                                     GFG{                       
           
                         public                                     static                                     void                                     main(String[] args)                       
                         {                       
                                                 String str =                                     "GeeksforGeeks"                                     ;                       
           
                                                 for                                     (                                     int                                     i =                                     0                                     ; i < str.length(); i++)                       
                                                 {                       
                                                 int                                     flag =                                     0                                     ;                       
                                                 for                                     (                                     int                                     j =                                     0                                     ; j < str.length(); j++)                       
                                                 {                       
                                                 // checking if two characters are equal                       
                                                 if                                     (str.charAt(i) == str.charAt(j) && i != j)                       
                                                 {                       
                                                 flag =                                     1                                     ;                       
                                                 break                                     ;                       
                                                 }                       
                                                 }                       
                                                 if                                     (flag ==                                     0                                     )                       
                                                 System.out.print(str.charAt(i));                       
                                                 }                       
                         }                       
                         }                       
           
                         // This code is contributed by gauravrajput1                       

Python3

                         string                                     =                                     "GeeksforGeeks"                       
           
                         for                                     i                                     in                                     range                                     (                                     0                                     ,                                     len                                     (string)):                       
                                                 flag                                     =                                     0                       
                                                 for                                     j                                     in                                     range                                     (                                     0                                     ,                                     len                                     (string)):                       
                                                 #checking if two characters are equal                       
                                                 if                                     (string[i]                                     =                                     =                                     string[j]                                     and                                     i!                                     =                                     j):                       
                                                 flag                                     =                                     1                       
                                                 break                       
                                                 if                                     (flag                                     =                                     =                                     0                                     ):                       
                                                 print                                     (string[i],end                                     =                                     "")                       

C#

                         using                                     System;                       
           
                         public                                     class                                     GFG{                       
           
                         public                                     static                                     void                                     Main(String[] args)                       
                         {                       
                                                 String str =                                     "GeeksforGeeks"                                     ;                       
           
                                                 for                                     (                                     int                                     i = 0; i < str.Length; i++)                       
                                                 {                       
                                                 int                                     flag = 0;                       
                                                 for                                     (                                     int                                     j = 0; j < str.Length; j++)                       
                                                 {                       
                                                 // checking if two characters are equal                       
                                                 if                                     (str[i] == str[j] && i != j)                       
                                                 {                       
                                                 flag = 1;                       
                                                 break                                     ;                       
                                                 }                       
                                                 }                       
                                                 if                                     (flag == 0)                       
                                                 Console.Write(str[i]);                       
                                                 }                       
                         }                       
                         }                       
           
                         // This code is contributed by gauravrajput1                       

Javascript

                         <script>                       
                                                 var                                     str =                                     "GeeksforGeeks"                                     ;                       
           
                                                 for                                     (                                     var                                     i = 0; i < str.length; i++) {                       
                                                 var                                     flag = 0;                       
                                                 for                                     (j = 0; j < str.length; j++) {                       
                                                 // checking if two characters are equal                       
                                                 if                                     (str.charAt(i) == str.charAt(j) && i != j) {                       
                                                 flag = 1;                       
                                                 break                                     ;                       
                                                 }                       
                                                 }                       
                                                 if                                     (flag == 0)                       
                                                 document.write(str.charAt(i));                       
                                                 }                       
           
                         // This code is contributed by gauravrajput1                       
                         </script>                       

输出

for

方法2（有效但需要两次遍历：O（n））

创建数组count[]以存储字符数。
遍历输入字符串str，并对每个字符x=str[i]执行以下操作。增量计数[x]。
再次遍历输入字符串，并对每个字符str[i]执行以下操作
1. 如果计数[x]为1，则打印唯一字符
2. 如果计数[x]大于1，则忽略重复的字符。

下面是上述想法的实现。

C++

                         // C++ program to print distinct characters of a                       
                         // string.                       
                         # include <iostream>                       
                         using                                     namespace                                     std;                       
                         # define NO_OF_CHARS 256                       
           
                         /* Print duplicates present in the passed string */                       
                         void                                     printDistinct(                                     char                                     *str)                       
                         {                       
                                                 // Create an array of size 256 and count of                       
                                                 // every character in it                       
                                                 int                                     count[NO_OF_CHARS];                       
           
                                                 /* Count array with frequency of characters */                       
                                                 int                                     i;                       
                                                 for                                     (i = 0; *(str+i); i++)                       
                                                 if                                     (*(str+i)!=                                     ' '                                     )                       
                                                 count[*(str+i)]++;                       
                                                 int                                     n = i;                       
           
                                                 // Print characters having count more than 0                       
                                                 for                                     (i = 0; i < n; i++)                       
                                                 if                                     (count[*(str+i)] == 1)                       
                                                 cout<< str[i];                       
                         }                       
           
                         /* Driver program*/                       
                         int                                     main()                       
                         {                       
                                                 char                                     str[] =                                     "GeeksforGeeks"                                     ;                       
                                                 printDistinct(str);                       
                                                 return                                     0;                       
                         }                       

JAVA

                         // Java program to print distinct characters of a                       
                         // string.                       
                         public                                     class                                     GFG {                       
                                                 static                                     final                                     int                                     NO_OF_CHARS =                                     256                                     ;                       
                                   
                                                 /* Print duplicates present in the passed string */                       
                                                 static                                     void                                     printDistinct(String str)                       
                                                 {                       
                                                 // Create an array of size 256 and count of                       
                                                 // every character in it                       
                                                 int                                     [] count =                                     new                                     int                                     [NO_OF_CHARS];                       
                                   
                                                 /* Count array with frequency of characters */                       
                                                 int                                     i;                       
                                                 for                                     (i =                                     0                                     ; i < str.length(); i++)                       
                                                 if                                     (str.charAt(i)!=                                     ' '                                     )                       
                                                 count[(                                     int                                     )str.charAt(i)]++;                       
                                                 int                                     n = i;                       
                                   
                                                 // Print characters having count more than 0                       
                                                 for                                     (i =                                     0                                     ; i < n; i++)                       
                                                 if                                     (count[(                                     int                                     )str.charAt(i)] ==                                     1                                     )                       
                                                 System.out.print(str.charAt(i));                       
                                                 }                       
                                   
                                                 /* Driver program*/                       
                                                 public                                     static                                     void                                     main(String args[])                       
                                                 {                       
                                                 String str =                                     "GeeksforGeeks"                                     ;                       
                                                 printDistinct(str);                       
                                                 }                       
                         }                       
                         // This code is contributed by Sumit Ghosh                       

Python3

                         # Python3 program to print distinct                       
                         # characters of a string.                       
                         NO_OF_CHARS                                     =                                     256                       
           
                         # Print duplicates present in the                       
                         # passed string                       
                         def                                     printDistinct(                                     str                                     ):                       
           
                                                 # Create an array of size 256 and                       
                                                 # count of every character in it                       
                                                 count                                     =                                     [                                     0                                     ]                                     *                                     NO_OF_CHARS                       
           
                                                 # Count array with frequency of                       
                                                 # characters                       
                                                 for                                     i                                     in                                     range                                     (                                     len                                     (                                     str                                     )):                       
                                                 if                                     (                                     str                                     [i] !                                     =                                     ' '                                     ):                       
                                                 count[                                     ord                                     (                                     str                                     [i])]                                     +                                     =                                     1                       
                                                 n                                     =                                     i                       
           
                                                 # Print characters having count                       
                                                 # more than 0                       
                                                 for                                     i                                     in                                     range                                     (n):                       
                                                 if                                     (count[                                     ord                                     (                                     str                                     [i])]                                     =                                     =                                     1                                     ):                       
                                                 print                                     (                                     str                                     [i], end                                     =                                     "")                       
           
                         # Driver Code                       
                         if                                     __name__                                     =                                     =                                     "__main__"                                     :                       
           
                                                 str                                     =                                     "GeeksforGeeks"                       
                                                 printDistinct(                                     str                                     )                       
                                   
                         # This code is contributed by ita_c                       

C#

                         // C# program to print distinct characters                       
                         // of a string.                       
                         using                                     System;                       
           
                         public                                     class                                     GFG {                       
                                   
                                                 static                                     int                                     NO_OF_CHARS = 256;                       
                                   
                                                 /* Print duplicates present in the                       
                                                 passed string */                       
                                                 static                                     void                                     printDistinct(String str)                       
                                                 {                       
                                   
                                                 // Create an array of size 256 and                       
                                                 // count of every character in it                       
                                                 int                                     [] count =                                     new                                     int                                     [NO_OF_CHARS];                       
                                   
                                                 /* Count array with frequency of                       
                                                 characters */                       
                                                 int                                     i;                       
                                   
                                                 for                                     (i = 0; i < str.Length; i++)                       
                                                 if                                     (str[i]!=                                     ' '                                     )                       
                                                 count[(                                     int                                     )str[i]]++;                       
                                   
                                                 int                                     n = i;                       
                                   
                                                 // Print characters having count                       
                                                 // more than 0                       
                                                 for                                     (i = 0; i < n; i++)                       
                                                 if                                     (count[(                                     int                                     )str[i]] == 1)                       
                                                 Console.Write(str[i]);                       
                                                 }                       
                                   
                                                 /* Driver program*/                       
                                                 public                                     static                                     void                                     Main()                       
                                                 {                       
                                                 String str =                                     "GeeksforGeeks"                                     ;                       
                                   
                                                 printDistinct(str);                       
                                                 }                       
                         }                       
           
                         // This code is contributed by parashar.                       

Javascript

                         <script>                       
                         // Javascript program to print distinct characters of a                       
                         // string.                       
           
                                                 let NO_OF_CHARS = 256;                       
                                   
                                                 /* Print duplicates present in the passed string */                       
                                                 function                                     printDistinct(str)                       
                                                 {                       
                                                 // Create an array of size 256 and count of                       
                                                 // every character in it                       
                                                 let count =                                     new                                     Array(NO_OF_CHARS);                       
                                                 for                                     (let i=0;i<NO_OF_CHARS;i++)                       
                                                 {                       
                                                 count[i]=0;                       
                                                 }                       
                                   
                                                 /* Count array with frequency of characters */                       
                                                 let i;                       
                                                 for                                     (i = 0; i < str.length; i++)                       
                                                 if                                     (str[i]!=                                     ' '                                     )                       
                                                 count[str[i].charCodeAt(0)]++;                       
                                                 let n = i;                       
                                   
                                                 // Print characters having count more than 0                       
                                                 for                                     (i = 0; i < n; i++)                       
                                                 if                                     (count[str[i].charCodeAt(0)] == 1)                       
                                                 document.write(str[i]);                       
                                                 }                       
                                   
                                                 /* Driver program*/                       
                                                 let str =                                     "GeeksforGeeks"                                     ;                       
                                                 printDistinct(str);                       
                                   
                                                 // This code is contributed by rag2127                       
                         </script>                       

输出：

for

方法3（O（n），需要一次遍历） 其想法是使用两个大小为256的辅助数组（假设字符存储使用8位）。

将计数[]中的所有值初始化为0，将索引[]中的所有值初始化为n，其中n是字符串的长度。
遍历输入字符串str，并对每个字符c=str[i]执行以下操作。
- 增量计数[x]。
- 如果计数[x]为1，则将x的索引存储在索引[x]中，即索引[x]=i
- 如果计数[x]为2，则从索引[]中删除x，即索引[x]=n
现在索引[]具有所有不同字符的索引。对索引进行排序并使用它打印字符。请注意，假设字符数是固定的（通常为256），这一步需要O（1）个时间

下面是上述想法的实现。

C++

                         // C++ program to find all distinct characters                       
                         // in a string                       
                         #include <bits/stdc++.h>                       
                         using                                     namespace                                     std;                       
                         const                                     int                                     MAX_CHAR = 256;                       
           
                         // Function to print distinct characters in                       
                         // given string str[]                       
                         void                                     printDistinct(string str)                       
                         {                       
                                                 int                                     n = str.length();                       
           
                                                 // count[x] is going to store count of                       
                                                 // character 'x' in str. If x is not present,                       
                                                 // then it is going to store 0.                       
                                                 int                                     count[MAX_CHAR];                       
           
                                                 // index[x] is going to store index of character                       
                                                 // 'x' in str. If x is not present or x is                       
                                                 // more than once, then it is going to store a value                       
                                                 // (for example, length of string) that cannot be                       
                                                 // a valid index in str[]                       
                                                 int                                     index[MAX_CHAR];                       
           
                                                 // Initialize counts of all characters and indexes                       
                                                 // of distinct characters.                       
                                                 for                                     (                                     int                                     i = 0; i < MAX_CHAR; i++)                       
                                                 {                       
                                                 count[i] = 0;                       
                                                 index[i] = n;                                     // A value more than any index                       
                                                 // in str[]                       
                                                 }                       
           
                                                 // Traverse the input string                       
                                                 for                                     (                                     int                                     i = 0; i < n; i++)                       
                                                 {                       
                                                 // Find current character and increment its                       
                                                 // count                       
                                                 char                                     x = str[i];                       
                                                 ++count[x];                       
           
                                                 // If this is first occurrence, then set value                       
                                                 // in index as index of it.                       
                                                 if                                     (count[x] == 1 && x !=                                     ' '                                     )                       
                                                 index[x] = i;                       
           
                                                 // If character repeats, then remove it from                       
                                                 // index[]                       
                                                 if                                     (count[x] == 2)                       
                                                 index[x] = n;                       
                                                 }                       
           
                                                 // Since size of index is constant, below operations                       
                                                 // take constant time.                       
                                                 sort(index, index+MAX_CHAR);                       
                                                 for                                     (                                     int                                     i=0; i<MAX_CHAR && index[i] != n; i++)                       
                                                 cout << str[index[i]];                       
                         }                       
           
                         // Driver code                       
                         int                                     main()                       
                         {                       
                                                 string str =                                     "GeeksforGeeks"                                     ;                       
                                                 printDistinct(str);                       
                                                 return                                     0;                       
                         }                       

JAVA

                         // Java program to print distinct characters of                       
                         // a string.                       
                         import                                     java.util.Arrays;                       
           
                         public                                     class                                     GFG {                       
                                   
                                                 static                                     final                                     int                                     MAX_CHAR =                                     256                                     ;                       
                                   
                                                 // Function to print distinct characters in                       
                                                 // given string str[]                       
                                                 static                                     void                                     printDistinct(String str)                       
                                                 {                       
                                                 int                                     n = str.length();                       
                                   
                                                 // count[x] is going to store count of                       
                                                 // character 'x' in str. If x is not present,                       
                                                 // then it is going to store 0.                       
                                                 int                                     [] count =                                     new                                     int                                     [MAX_CHAR];                       
                                   
                                                 // index[x] is going to store index of character                       
                                                 // 'x' in str. If x is not present or x is                       
                                                 // more than once, then it is going to store a                       
                                                 // value (for example, length of string) that                       
                                                 // cannot be a valid index in str[]                       
                                                 int                                     [] index =                                     new                                     int                                     [MAX_CHAR];                       
                                   
                                                 // Initialize counts of all characters and                       
                                                 // indexes of distinct characters.                       
                                                 for                                     (                                     int                                     i =                                     0                                     ; i < MAX_CHAR; i++)                       
                                                 {                       
                                                 count[i] =                                     0                                     ;                       
                                                 index[i] = n;                                     // A value more than any                       
                                                 // index in str[]                       
                                                 }                       
                                   
                                                 // Traverse the input string                       
                                                 for                                     (                                     int                                     i =                                     0                                     ; i < n; i++)                       
                                                 {                       
                                                 // Find current character and increment                       
                                                 // its count                       
                                                 char                                     x = str.charAt(i);                       
                                                 ++count[x];                       
                                   
                                                 // If this is first occurrence, then set                       
                                                 // value in index as index of it.                       
                                                 if                                     (count[x] ==                                     1                                     && x !=                                     ' '                                     )                       
                                                 index[x] = i;                       
                                   
                                                 // If character repeats, then remove it                       
                                                 // from index[]                       
                                                 if                                     (count[x] ==                                     2                                     )                       
                                                 index[x] = n;                       
                                                 }                       
                                   
                                                 // Since size of index is constant, below                       
                                                 // operations take constant time.                       
                                                 Arrays.sort(index);                       
                                   
                                                 for                                     (                                     int                                     i =                                     0                                     ; i < MAX_CHAR && index[i] != n;                       
                                                 i++)                       
                                                 System.out.print(str.charAt(index[i]));                       
                                                 }                       
                                   
                                                 // Driver code                       
                                                 public                                     static                                     void                                     main(String args[])                       
                                                 {                       
                                                 String str =                                     "GeeksforGeeks"                                     ;                       
                                                 printDistinct(str);                       
                                                 }                       
                         }                       
                         // This code is contributed by Sumit Ghosh                       

python

                         # Python3 program to find all distinct characters                       
                         # in a String                       
           
                         MAX_CHAR                                     =                                     256                       
           
                         # Function to print distinct characters in                       
                         # given Str[]                       
                         def                                     printDistinct(                                     Str                                     ):                       
           
                                                 n                                     =                                     len                                     (                                     Str                                     )                       
           
                                                 # count[x] is going to store count of                       
                                                 # character 'x' in Str. If x is not present,                       
                                                 # then it is going to store 0.                       
                                                 count                                     =                                     [                                     0                                     for                                     i                                     in                                     range                                     (MAX_CHAR)]                       
           
                                                 # index[x] is going to store index of character                       
                                                 # 'x' in Str. If x is not present or x is                       
                                                 # more than once, then it is going to store a value                       
                                                 # (for example, length of String) that cannot be                       
                                                 # a valid index in Str[]                       
                                                 index                                     =                                     [n                                     for                                     i                                     in                                     range                                     (MAX_CHAR)]                       
           
           
                                                 # Traverse the input String                       
                                                 for                                     i                                     in                                     range                                     (n):                       
                                   
                                                 # Find current character and increment its                       
                                                 # count                       
                                                 x                                     =                                     ord                                     (                                     Str                                     [i])                       
                                                 count[x]                                     +                                     =                                     1                       
           
                                                 # If this is first occurrence, then set value                       
                                                 # in index as index of it.                       
                                                 if                                     (count[x]                                     =                                     =                                     1                                     and                                     x !                                     =                                     ' '                                     ):                       
                                                 index[x]                                     =                                     i                       
           
                                                 # If character repeats, then remove it from                       
                                                 # index[]                       
                                                 if                                     (count[x]                                     =                                     =                                     2                                     ):                       
                                                 index[x]                                     =                                     n                       
           
           
                                                 # Since size of index is constant, below operations                       
                                                 # take constant time.                       
                                                 index                                     =                                     sorted                                     (index)                       
           
                                                 for                                     i                                     in                                     range                                     (MAX_CHAR):                       
                                                 if                                     index[i]                                     =                                     =                                     n:                       
                                                 break                       
                                                 print                                     (                                     Str                                     [index[i]],end                                     =                                     "")                       
           
                         # Driver code                       
           
                         Str                                     =                                     "GeeksforGeeks"                       
                         printDistinct(                                     Str                                     )                       
           
                         # This code is contributed by mohit kumar 29                       

C#

                         // C# program to print distinct characters of                       
                         // a string.                       
                         using                                     System;                       
           
                         public                                     class                                     GFG {                       
                                   
                                                 static                                     int                                     MAX_CHAR = 256;                       
                                   
                                                 // Function to print distinct characters in                       
                                                 // given string str[]                       
                                                 static                                     void                                     printDistinct(                                     string                                     str)                       
                                                 {                       
                                                 int                                     n = str.Length;                       
                                   
                                                 // count[x] is going to store count of                       
                                                 // character 'x' in str. If x is not                       
                                                 // present, then it is going to store 0.                       
                                                 int                                     []count =                                     new                                     int                                     [MAX_CHAR];                       
                                   
                                                 // index[x] is going to store index of                       
                                                 // character 'x' in str. If x is not                       
                                                 // present or x is more than once, then                       
                                                 // it is going to store a value (for                       
                                                 // example, length of string) that                       
                                                 // cannot be a valid index in str[]                       
                                                 int                                     []index =                                     new                                     int                                     [MAX_CHAR];                       
                                   
                                                 // Initialize counts of all characters                       
                                                 // and indexes of distinct characters.                       
                                                 for                                     (                                     int                                     i = 0; i < MAX_CHAR; i++)                       
                                                 {                       
                                                 count[i] = 0;                       
                                   
                                                 // A value more than any index                       
                                                 // in str[]                       
                                                 index[i] = n;                       
                                   
                                                 }                       
                                   
                                                 // Traverse the input string                       
                                                 for                                     (                                     int                                     i = 0; i < n; i++)                       
                                                 {                       
                                                 // Find current character and                       
                                                 // increment its count                       
                                                 char                                     x = str[i];                       
                                                 ++count[x];                       
                                   
                                                 // If this is first occurrence, then                       
                                                 // set value in index as index of it.                       
                                                 if                                     (count[x] == 1 && x !=                                     ' '                                     )                       
                                                 index[x] = i;                       
                                   
                                                 // If character repeats, then remove                       
                                                 // it from index[]                       
                                                 if                                     (count[x] == 2)                       
                                                 index[x] = n;                       
                                                 }                       
                                   
                                                 // Since size of index is constant, below                       
                                                 // operations take constant time.                       
                                                 Array.Sort(index);                       
                                   
                                                 for                                     (                                     int                                     i = 0; i < MAX_CHAR &&                       
                                                 index[i] != n; i++)                       
                                                 Console.Write(str[index[i]]);                       
                                                 }                       
                                   
                                                 // Driver code                       
                                                 public                                     static                                     void                                     Main()                       
                                                 {                       
                                                 string                                     str =                                     "GeeksforGeeks"                                     ;                       
                                                 printDistinct(str);                       
                                                 }                       
                         }                       
           
                         // This code is contributed by nitin mittal.                       

Javascript

                         <script>                       
                         // Javascript program to print distinct characters of                       
                         // a string.                       
                                   
                                                 let MAX_CHAR = 256;                       
                                   
                                                 // Function to print distinct characters in                       
                                                 // given string str[]                       
                                                 function                                     printDistinct(str)                       
                                                 {                       
                                                 let n = str.length;                       
                                   
                                                 // count[x] is going to store count of                       
                                                 // character 'x' in str. If x is not present,                       
                                                 // then it is going to store 0.                       
                                                 let count =                                     new                                     Array(MAX_CHAR);                       
                                   
                                                 // index[x] is going to store index of character                       
                                                 // 'x' in str. If x is not present or x is                       
                                                 // more than once, then it is going to store a                       
                                                 // value (for example, length of string) that                       
                                                 // cannot be a valid index in str[]                       
                                                 let index =                                     new                                     Array(MAX_CHAR);                       
                                   
                                                 // Initialize counts of all characters and                       
                                                 // indexes of distinct characters.                       
                                                 for                                     (let i = 0; i < MAX_CHAR; i++)                       
                                                 {                       
                                                 count[i] = 0;                       
                                                 index[i] = n;                                     // A value more than any                       
                                                 // index in str[]                       
                                                 }                       
                                   
                                                 // Traverse the input string                       
                                                 for                                     (let i = 0; i < n; i++)                       
                                                 {                       
                                                 // Find current character and increment                       
                                                 // its count                       
                                                 let x = str[i].charCodeAt(0);                       
                                                 ++count[x];                       
                                   
                                                 // If this is first occurrence, then set                       
                                                 // value in index as index of it.                       
                                                 if                                     (count[x] == 1 && x !=                                     ' '                                     )                       
                                                 index[x] = i;                       
                                   
                                                 // If character repeats, then remove it                       
                                                 // from index[]                       
                                                 if                                     (count[x] == 2)                       
                                                 index[x] = n;                       
                                                 }                       
                                   
                                                 // Since size of index is constant, below                       
                                                 // operations take constant time.                       
                                                 index.sort(                                     function                                     (a,b){                                     return                                     a-b});                       
                                   
                                                 for                                     (let i = 0; i < MAX_CHAR && index[i] != n;                       
                                                 i++)                       
                                                 document.write(str[index[i]]);                       
                                                 }                       
                                   
                                                 // Driver code                       
                                                 let str =                                     "GeeksforGeeks"                                     ;                       
                                                 printDistinct(str);                       
                                   
                                   
                                                 // This code is contributed by avanitrachhadiya2155                       
                         </script>                       

输出

for

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