反转保留空间位置的字符串-yiteyi-C++库

编写一个程序来反转给定的字符串，同时保留空格的位置。

null

例如：

Input  : "abc de"Output : edc baInput : "intern at geeks"Output : skeegt an retniInput : "Help others"Output : sreh topleH

图片[1]-反转保留空间位置的字符串-yiteyi-C++库

建议：请在“上解决” 实践 “首先，在讨论解决方案之前。

创建一个字符串来存储结果。标记给定字符串在该字符串中的空格位置。
将输入字符串中的字符按相反顺序插入结果字符串。
插入字符时，检查结果字符串是否在索引“j”处包含空格。如果包含，我们将角色复制到下一个位置。

以下是上述步骤的实施情况。

C++

                         // C++ program to reverse a string preserving                       
                         // spaces.                       
                         #include <iostream>                       
                         using                                     namespace                                     std;                       
           
                         // Function to reverse the string                       
                         // and preserve the space position                       
                         string reverses(string str)                       
                         {                       
                                                 // Mark spaces in result                       
                                                 int                                     n = str.size();                       
                                                 string result(n,                                     ' '                                     );                       
                                                 for                                     (                                     int                                     i = 0; i < n; i++)                       
                                                 if                                     (str[i] ==                                     ' '                                     )                       
                                                 result[i] =                                     ' '                                     ;                       
           
                                                 // Traverse input string from beginning                       
                                                 // and put characters in result from end                       
                                                 int                                     j = n - 1;                       
                                                 for                                     (                                     int                                     i = 0; i < str.length(); i++) {                       
                                                 // Ignore spaces in input string                       
                                                 if                                     (str[i] !=                                     ' '                                     ) {                       
                                                 // ignore spaces in result.                       
                                                 while                                     (result[j] ==                                     ' '                                     )                       
                                                 j--;                       
           
                                                 result[j] = str[i];                       
                                                 j--;                       
                                                 }                       
                                                 }                       
           
                                                 return                                     result;                       
                         }                       
           
                         // Driver code                       
                         int                                     main()                       
                         {                       
                                                 string str =                                     "internship at geeks for geeks"                                     ;                       
                                                 cout << reverses(str) << endl;                       
                                                 return                                     0;                       
                         }                       

JAVA

                         // Java program to reverse a string                       
                         // preserving spaces.                       
                         public                                     class                                     ReverseStringPreserveSpace {                       
                                                 // Function to reverse the string                       
                                                 // and preserve the space position                       
                                                 static                                     void                                     reverses(String str)                       
                                                 {                       
           
                                                 char                                     [] inputArray = str.toCharArray();                       
                                                 char                                     [] result =                                     new                                     char                                     [inputArray.length];                       
           
                                                 // Mark spaces in result                       
                                                 for                                     (                                     int                                     i =                                     0                                     ; i < inputArray.length; i++) {                       
                                                 if                                     (inputArray[i] ==                                     ' '                                     ) {                       
                                                 result[i] =                                     ' '                                     ;                       
                                                 }                       
                                                 }                       
           
                                                 // Traverse input string from beginning                       
                                                 // and put characters in result from end                       
                                                 int                                     j = result.length -                                     1                                     ;                       
                                                 for                                     (                                     int                                     i =                                     0                                     ; i < inputArray.length; i++) {                       
           
                                                 // Ignore spaces in input string                       
                                                 if                                     (inputArray[i] !=                                     ' '                                     ) {                       
           
                                                 // ignore spaces in result.                       
                                                 if                                     (result[j] ==                                     ' '                                     ) {                       
                                                 j--;                       
                                                 }                       
                                                 result[j] = inputArray[i];                       
                                                 j--;                       
                                                 }                       
                                                 }                       
                                                 System.out.println(String.valueOf(result));                       
                                                 }                       
           
                                                 // driver function                       
                                                 public                                     static                                     void                                     main(String[] args)                       
                                                 {                       
                                                 reverses(                                     "internship at geeks for geeks"                                     );                       
                                                 }                       
                         }                       
           
                         // This code is contributed by Rishabh Jain                       

Python3

                         # Python3 program to reverse a string preserving                       
                         # spaces.                       
           
                         # Function to reverse the string                       
                         # and preserve the space position                       
                         def                                     reverses(st):                       
           
                                                 # Mark spaces in result                       
                                                 n                                     =                                     len                                     (st)                       
                                                 result                                     =                                     [                                     0                                     ]                                     *                                     n                       
                                   
                                                 for                                     i                                     in                                     range                                     (n):                       
                                                 if                                     (st[i]                                     =                                     =                                     ' '                                     ):                       
                                                 result[i]                                     =                                     ' '                       
           
                                                 # Traverse input string from beginning                       
                                                 # and put characters in result from end                       
                                                 j                                     =                                     n                                     -                                     1                       
                                                 for                                     i                                     in                                     range                                     (                                     len                                     (st)):                       
                                   
                                                 # Ignore spaces in input string                       
                                                 if                                     (st[i] !                                     =                                     ' '                                     ):                       
                                   
                                                 # Ignore spaces in result.                       
                                                 if                                     (result[j]                                     =                                     =                                     ' '                                     ):                       
                                                 j                                     -                                     =                                     1                       
           
                                                 result[j]                                     =                                     st[i]                       
                                                 j                                     -                                     =                                     1                       
                                   
                                                 return                                     ''.join(result)                       
           
                         # Driver code                       
                         if                                     __name__                                     =                                     =                                     "__main__"                                     :                       
           
                                                 st                                     =                                     "internship at geeks for geeks"                       
                                                 print                                     (reverses(st))                       
           
                         # This code is contributed by ukasp                       

C#

                         // C# program to reverse a                       
                         // string preserving spaces.                       
                         using                                     System;                       
           
                         class                                     GFG {                       
           
                                                 // Function to reverse the string                       
                                                 // and preserve the space position                       
                                                 static                                     void                                     reverses(                                     string                                     str)                       
                                                 {                       
                                                 char                                     [] inputArray = str.ToCharArray();                       
                                                 char                                     [] result =                                     new                                     char                                     [inputArray.Length];                       
           
                                                 // Mark spaces in result                       
                                                 for                                     (                                     int                                     i = 0; i < inputArray.Length; i++) {                       
                                                 if                                     (inputArray[i] ==                                     ' '                                     ) {                       
                                                 result[i] =                                     ' '                                     ;                       
                                                 }                       
                                                 }                       
           
                                                 // Traverse input string from beginning                       
                                                 // and put characters in result from end                       
                                                 int                                     j = result.Length - 1;                       
                                                 for                                     (                                     int                                     i = 0; i < inputArray.Length; i++) {                       
           
                                                 // Ignore spaces in input string                       
                                                 if                                     (inputArray[i] !=                                     ' '                                     ) {                       
           
                                                 // ignore spaces in result.                       
                                                 if                                     (result[j] ==                                     ' '                                     ) {                       
                                                 j--;                       
                                                 }                       
                                                 result[j] = inputArray[i];                       
                                                 j--;                       
                                                 }                       
                                                 }                       
                                                 for                                     (                                     int                                     i = 0; i < result.Length; i++)                       
                                                 Console.Write(result[i]);                       
                                                 }                       
           
                                                 // Driver code                       
                                                 public                                     static                                     void                                     Main()                       
                                                 {                       
                                                 reverses(                                     "internship at geeks for geeks"                                     );                       
                                                 }                       
                         }                       
           
                         // This code is contributed by Sam007                       

Javascript

                         <script>                       
                         // Javascript program to reverse a string                       
                         // preserving spaces.                       
           
                         // Function to reverse the string                       
                                                 // and preserve the space position                       
                         function                                     reverses(str)                       
                         {                       
                                                 let inputArray = str.split(                                     ""                                     );                       
                                                 let result =                                     new                                     Array(inputArray.length);                       
                                   
                                                 // Mark spaces in result                       
                                                 for                                     (let i = 0; i < inputArray.length; i++) {                       
                                                 if                                     (inputArray[i] ==                                     ' '                                     ) {                       
                                                 result[i] =                                     ' '                                     ;                       
                                                 }                       
                                                 }                       
                                   
                                                 // Traverse input string from beginning                       
                                                 // and put characters in result from end                       
                                                 let j = result.length - 1;                       
                                                 for                                     (let i = 0; i < inputArray.length; i++) {                       
                                   
                                                 // Ignore spaces in input string                       
                                                 if                                     (inputArray[i] !=                                     ' '                                     ) {                       
                                   
                                                 // ignore spaces in result.                       
                                                 if                                     (result[j] ==                                     ' '                                     ) {                       
                                                 j--;                       
                                                 }                       
                                                 result[j] = inputArray[i];                       
                                                 j--;                       
                                                 }                       
                                                 }                       
                                                 document.write((result).join(                                     ""                                     ));                       
                         }                       
                         // driver function                       
                         reverses(                                     "internship at geeks for geeks"                                     );                       
           
           
                         // This code is contributed by ab2127                       
                         </script>                       

输出：

skeegrofsk ee gtapi hsn retni

时间复杂度->O（N）辅助空间->O（N）

优化方案 这个想法是使用两个指针来反转。

C++

                         // C++ program to implement                       
                         // the above approach                       
                         #include <iostream>                       
                         using                                     namespace                                     std;                       
           
                         void                                     preserveSpace(string &str)                       
                         {                       
                                                 int                                     n = str.length();                       
           
                                                 // Initialize two pointers as two corners                       
                                                 int                                     start = 0;                       
                                                 int                                     end = n - 1;                       
           
                                                 // Move both pointers toward each other                       
                                                 while                                     (start < end) {                       
           
                                                 // If character at start or end is space,                       
                                                 // ignore it                       
                                                 if                                     (str[start] ==                                     ' '                                     ) {                       
                                                 start++;                       
                                                 continue                                     ;                       
                                                 }                       
                                                 else                                     if                                     (str[end] ==                                     ' '                                     ) {                       
                                                 end--;                       
                                                 continue                                     ;                       
                                                 }                       
           
                                                 // If both are not spaces, do swap                       
                                                 else                                     {                       
                                                 swap(str[start], str[end]);                       
                                                 start++;                       
                                                 end--;                       
                                                 }                       
                                                 }                       
                         }                       
           
                         // Driver code                       
                         int                                     main()                       
                         {                       
                                                 string str =                                     "internship at geeks for geeks"                                     ;                       
                                                 preserveSpace(str);                       
                                                 cout << str;                       
                                                 return                                     0;                       
                         }                       

JAVA

                         // Java program to implement                       
                         // the above approach                       
                         import                                     java.io.*;                       
                         import                                     java.util.*;                       
           
                         class                                     GFG{                       
                                   
                         public                                     static                                     void                                     preserveSpace(String str)                       
                         {                       
                                                 int                                     n = str.length();                       
                                   
                                                 // Initialize two pointers as two corners                       
                                                 int                                     start =                                     0                                     ;                       
                                                 int                                     end = n -                                     1                                     ;                       
                                   
                                                 char                                     [] Str = str.toCharArray();                       
                                   
                                                 // Move both pointers toward each other                       
                                                 while                                     (start < end)                       
                                                 {                       
                                   
                                                 // If character at start or end                       
                                                 // is space, ignore it                       
                                                 if                                     (Str[start] ==                                     ' '                                     )                       
                                                 {                       
                                                 start++;                       
                                                 continue                                     ;                       
                                                 }                       
                                                 else                                     if                                     (Str[end] ==                                     ' '                                     )                       
                                                 {                       
                                                 end--;                       
                                                 continue                                     ;                       
                                                 }                       
                                   
                                                 // If both are not spaces, do swap                       
                                                 else                       
                                                 {                       
                                                 char                                     temp = Str[start];                       
                                                 Str[start] = Str[end];                       
                                                 Str[end] = temp;                       
                                                 start++;                       
                                                 end--;                       
                                                 }                       
                                                 }                       
                                                 System.out.println(String.valueOf(Str));                       
                         }                       
           
                         // Driver Code                       
                         public                                     static                                     void                                     main(String[] args)                       
                         {                       
                                                 String str =                                     "internship at geeks for geeks"                                     ;                       
                                   
                                                 preserveSpace(str);                       
                         }                       
                         }                       
           
                         // This code is contributed by divyeshrabadiya07                       

Python3

                         # Python3 program to implement                       
                         # the above approach                       
                         def                                     preserveSpace(                                     Str                                     ):                       
                                   
                                                 n                                     =                                     len                                     (                                     Str                                     )                       
                                                 Str                                     =                                     list                                     (                                     Str                                     )                       
           
                                                 # Initialize two pointers                       
                                                 # as two corners                       
                                                 start                                     =                                     0                       
                                                 end                                     =                                     n                                     -                                     1                       
           
                                                 # Move both pointers                       
                                                 # toward each other                       
                                                 while                                     (start < end):                       
           
                                                 # If character at start                       
                                                 # or end is space,                       
                                                 # ignore it                       
                                                 if                                     (                                     Str                                     [start]                                     =                                     =                                     ' '                                     ):                       
                                                 start                                     +                                     =                                     1                       
                                                 continue                       
                                                 elif                                     (                                     Str                                     [end]                                     =                                     =                                     ' '                                     ):                       
                                                 end                                     -                                     =                                     1                       
                                                 continue                       
                                   
                                                 # If both are not                       
                                                 # spaces, do swap                       
                                                 else                                     :                       
                                                 Str                                     [start],                                     Str                                     [end]                                     =                                     (                                     Str                                     [end],                       
                                                 Str                                     [start])                       
                                                 start                                     +                                     =                                     1                       
                                                 end                                     -                                     =                                     1                       
                                                 print                                     (''.join(                                     Str                                     ))                       
           
                         # Driver code                       
                         Str                                     =                                     "internship at geeks for geeks"                       
                         preserveSpace(                                     Str                                     );                       
           
                         # This code is contributed by avanitrachhadiya2155                       

C#

                         // C# program to implement                       
                         // the above approach                       
                         using                                     System;                       
                         using                                     System.Collections.Generic;                       
           
                         class                                     GFG{                       
                                   
                         static                                     void                                     preserveSpace(                                     string                                     str)                       
                         {                       
                                                 int                                     n = str.Length;                       
                                   
                                                 // Initialize two pointers                       
                                                 // as two corners                       
                                                 int                                     start = 0;                       
                                                 int                                     end = n - 1;                       
                                   
                                                 char                                     [] Str = str.ToCharArray();                       
                                   
                                                 // Move both pointers toward                       
                                                 // each other                       
                                                 while                                     (start < end)                       
                                                 {                       
                                   
                                                 // If character at start or                       
                                                 // end is space, ignore it                       
                                                 if                                     (Str[start] ==                                     ' '                                     )                       
                                                 {                       
                                                 start++;                       
                                                 continue                                     ;                       
                                                 }                       
                                                 else                                     if                                     (Str[end] ==                                     ' '                                     )                       
                                                 {                       
                                                 end--;                       
                                                 continue                                     ;                       
                                                 }                       
                                   
                                                 // If both are not spaces, do swap                       
                                                 else                       
                                                 {                       
                                                 char                                     temp = Str[start];                       
                                                 Str[start] = Str[end];                       
                                                 Str[end] = temp;                       
                                                 start++;                       
                                                 end--;                       
                                                 }                       
                                                 }                       
                                                 Console.Write(                                     new                                     string                                     (Str));                       
                         }                       
           
                         // Driver code                       
                         static                                     void                                     Main()                       
                         {                       
                                                 string                                     str =                                     "internship at geeks for geeks"                                     ;                       
                                   
                                                 preserveSpace(str);                       
                         }                       
                         }                       
           
                         // This code is contributed by divyesh072019                       

Javascript

                         <script>                       
           
                                                 // Javascript program to implement                       
                                                 // the above approach                       
                                   
                                                 function                                     preserveSpace(str)                       
                                                 {                       
                                                 let n = str.length;                       
           
                                                 // Initialize two pointers                       
                                                 // as two corners                       
                                                 let start = 0;                       
                                                 let end = n - 1;                       
           
                                                 let Str = str.split(                                     ''                                     );                       
           
                                                 // Move both pointers toward                       
                                                 // each other                       
                                                 while                                     (start < end)                       
                                                 {                       
           
                                                 // If character at start or                       
                                                 // end is space, ignore it                       
                                                 if                                     (Str[start] ==                                     ' '                                     )                       
                                                 {                       
                                                 start++;                       
                                                 continue                                     ;                       
                                                 }                       
                                                 else                                     if                                     (Str[end] ==                                     ' '                                     )                       
                                                 {                       
                                                 end--;                       
                                                 continue                                     ;                       
                                                 }                       
           
                                                 // If both are not spaces, do swap                       
                                                 else                       
                                                 {                       
                                                 let temp = Str[start];                       
                                                 Str[start] = Str[end];                       
                                                 Str[end] = temp;                       
                                                 start++;                       
                                                 end--;                       
                                                 }                       
                                                 }                       
                                                 document.write(Str.join(                                     ""                                     ));                       
                                                 }                       
                                   
                                                 let str =                                     "internship at geeks for geeks"                                     ;                       
                                   
                                                 preserveSpace(str);                       
           
                         </script>                       

输出：

skeegrofsk ee gtapi hsn retni

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