按相对顺序打印数组中最后出现的元素-yiteyi-C++库

给定一个由N个元素组成的数组，通过删除除最后一个元素外的所有元素引用，以与给定相同的相对顺序打印元素。例子 :

null

输入： a[]={1,5,5,1,6,1} 输出： 5 6 1 删除位置1和4中的两个整数1。此外，删除位于位置2的整数5。因此，左边的数组是{5,6,1} 输入： a[]={2,5,5,2} 输出： 5 2

推荐：请尝试你的方法 {IDE} 首先，在进入解决方案之前。

方法：

散列每个元素的最后一次出现。
迭代N个元素的数组，如果元素的索引是散列的，那么打印数组元素。

以下是上述方法的实施情况：

C++

                         // C++ program to print the last occurrence                       
                         // of every element in relative order                       
                         #include <bits/stdc++.h>                       
                         using                                     namespace                                     std;                       
           
                         // Function to print the last occurrence                       
                         // of every element in an array                       
                         void                                     printLastOccurrence(                                     int                                     a[],                                     int                                     n)                       
                         {                       
           
                                                 // used in hashing                       
                                                 unordered_map<                                     int                                     ,                                     int                                     > mp;                       
           
                                                 // iterate and store the last index                       
                                                 // of every element                       
                                                 for                                     (                                     int                                     i = 0; i < n; i++)                       
                                                 mp[a[i]] = i;                       
           
                                                 // iterate and check for the last                       
                                                 // occurrence of every element                       
                                                 for                                     (                                     int                                     i = 0; i < n; i++) {                       
                                                 if                                     (mp[a[i]] == i)                       
                                                 cout << a[i] <<                                     " "                                     ;                       
                                                 }                       
                         }                       
                         // Driver Code                       
                         int                                     main()                       
                         {                       
                                                 int                                     a[] = { 1, 5, 5, 1, 6, 1 };                       
                                                 int                                     n =                                     sizeof                                     (a) /                                     sizeof                                     (a[0]);                       
                                                 printLastOccurrence(a, n);                       
           
                                                 return                                     0;                       
                         }                       

JAVA

                         // Java program to print the                       
                         // last occurrence of every                       
                         // element in relative order                       
                         import                                     java.util.*;                       
           
                         class                                     GFG                       
                         {                       
                                   
                                                 // Function to print the last                       
                                                 // occurrence of every element                       
                                                 // in an array                       
                                                 public                                     static                                     void                                     printLastOccurrence(                                     int                                     a[],                       
                                                 int                                     n)                       
                                                 {                       
                                                 HashMap<Integer,                       
                                                 Integer> map =                                     new                                     HashMap<Integer,                       
                                                 Integer>();                       
                                   
                                                 // iterate and store the last                       
                                                 // index of every element                       
                                                 for                                     (                                     int                                     i =                                     0                                     ; i < n; i++)                       
                                                 map.put(a[i], i);                       
                                   
                                                 for                                     (                                     int                                     i =                                     0                                     ; i < n; i++)                       
                                                 {                       
                                                 if                                     (map.get(a[i]) == i)                       
                                                 System.out.print(a[i] +                                     " "                                     );                       
                                                 }                       
                                                 }                       
                                   
                                                 // Driver Code                       
                                                 public                                     static                                     void                                     main (String[] args)                       
                                                 {                       
                                                 int                                     a[] = {                                     1                                     ,                                     5                                     ,                                     5                                     ,                                     1                                     ,                                     6                                     ,                                     1                                     };                       
                                                 int                                     n = a.length;                       
                                                 printLastOccurrence(a, n);                       
                                                 }                       
                         }                       
           
                         // This code is contributed                       
                         // by ankita_saini                       

Python3

                         # Python 3 program to print the last occurrence                       
                         # of every element in relative order                       
           
                         # Function to print the last occurrence                       
                         # of every element in an array                       
                         def                                     printLastOccurrence(a, n):                       
                                   
                                                 # used in hashing                       
                                                 mp                                     =                                     {i:                                     0                                     for                                     i                                     in                                     range                                     (                                     7                                     )}                       
           
                                                 # iterate and store the last                       
                                                 # index of every element                       
                                                 for                                     i                                     in                                     range                                     (n):                       
                                                 mp[a[i]]                                     =                                     i                       
           
                                                 # iterate and check for the last                       
                                                 # occurrence of every element                       
                                                 for                                     i                                     in                                     range                                     (n):                       
                                                 if                                     (mp[a[i]]                                     =                                     =                                     i):                       
                                                 print                                     (a[i], end                                     =                                     " "                                     )                       
           
                         # Driver Code                       
                         if                                     __name__                                     =                                     =                                     '__main__'                                     :                       
                                                 a                                     =                                     [                                     1                                     ,                                     5                                     ,                                     5                                     ,                                     1                                     ,                                     6                                     ,                                     1                                     ]                       
                                                 n                                     =                                     len                                     (a)                       
                                                 printLastOccurrence(a, n)                       
           
                         # This code is contributed by                       
                         # Surendra_Gangwar                       

C#

                         // C# program to print the                       
                         // last occurrence of every                       
                         // element in relative order                       
                         using                                     System;                       
           
                         class                                     GFG                       
                         {                       
                                   
                         // Function to print the last                       
                         // occurrence of every element                       
                         // in an array                       
                         public                                     static                                     void                                     printLastOccurrence(                                     int                                     [] a,                       
                                                 int                                     n)                       
                         {                       
                                                 HashMap<Integer,                       
                                                 Integer> map =                                     new                                     HashMap<Integer,                       
                                                 Integer>();                       
                                   
                                                 // iterate and store the last                       
                                                 // index of every element                       
                                                 for                                     (                                     int                                     i = 0; i < n; i++)                       
                                                 map.put(a[i], i);                       
                                   
                                                 for                                     (                                     int                                     i = 0; i < n; i++)                       
                                                 {                       
                                                 if                                     (map.                                     get                                     (a[i]) == i)                       
                                                 Console.Write(a[i] +                                     " "                                     );                       
                                                 }                       
                         }                       
           
                         // Driver Code                       
                         public                                     static                                     void                                     Main ()                       
                         {                       
                                                 int                                     [] a = { 1, 5, 5, 1, 6, 1 };                       
                                                 int                                     n = a.Length;                       
                                                 printLastOccurrence(a, n);                       
                         }                       
                         }                       
           
                         // This code is contributed                       
                         // by ChitraNayal                       

PHP

                         <?php                       
                         // PHP program to print the last                       
                         // occurrence of every element                       
                         // in relative order                       
           
                         // Function to print the last                       
                         // occurrence of every element                       
                         // in an array                       
                         function                                     printLastOccurrence(&                                     $a                                     ,                                     $n                                     )                       
                         {                       
           
                                                 // used in hashing                       
                                                 $mp                                     =                                     array                                     ();                       
           
                                                 // iterate and store the last                       
                                                 // index of every element                       
                                                 for                                     (                                     $i                                     = 0;                                     $i                                     <                                     $n                                     ;                                     $i                                     ++)                       
                                                 $mp                                     [                                     $a                                     [                                     $i                                     ]] =                                     $i                                     ;                       
           
                                                 // iterate and check for the last                       
                                                 // occurrence of every element                       
                                                 for                                     (                                     $i                                     = 0;                                     $i                                     <                                     $n                                     ;                                     $i                                     ++)                       
                                                 {                       
                                                 if                                     (                                     $mp                                     [                                     $a                                     [                                     $i                                     ]] ==                                     $i                                     )                       
                                                 echo                                     $a                                     [                                     $i                                     ] .                                     " "                                     ;                       
                                                 }                       
                         }                       
           
                         // Driver Code                       
                         $a                                     =                                     array                                     (1, 5, 5, 1, 6, 1);                       
                         $n                                     = sizeof(                                     $a                                     );                       
                         printLastOccurrence(                                     $a                                     ,                                     $n                                     );                       
           
                         // This code is contributed                       
                         // by ChitraNayal                       
                         ?>                       

Javascript

                         <script>                       
           
                         // Javascript program to print the last                       
                         // occurrence of every element                       
                         // in relative order                       
           
                         // Function to print the last                       
                         // occurrence of every element                       
                         // in an array                       
                         function                                     printLastOccurrence(a, n)                       
                         {                       
           
                                                 // used in hashing                       
                                                 let mp = [];                       
           
                                                 // iterate and store the last                       
                                                 // index of every element                       
                                                 for                                     (let i = 0; i < n; i++)                       
                                                 mp[a[i]] = i;                       
           
                                                 // iterate and check for the last                       
                                                 // occurrence of every element                       
                                                 for                                     (let i = 0; i < n; i++)                       
                                                 {                       
                                                 if                                     (mp[a[i]] == i)                       
                                                 document.write( a[i] +                                     " "                                     );                       
                                                 }                       
                         }                       
           
                         // Driver Code                       
                         let a = [1, 5, 5, 1, 6, 1];                       
                         let n = a.length;                       
                         printLastOccurrence(a, n);                       
           
           
                         // This code is contributed by sravan kumar                       
           
                         </script>                       

输出：

5 6 1

时间复杂性： O（N*logn）

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