替代排序-yiteyi-C++库

给定一个整数数组，以这样的方式打印数组：第一个元素是第一个最大值，第二个元素是第一个最小值，依此类推。 例如：

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Input : arr[] = {7, 1, 2, 3, 4, 5, 6}Output : 7 1 6 2 5 3 4Input : arr[] = {1, 6, 9, 4, 3, 7, 8, 2}Output : 9 1 8 2 7 3 6 4

建议：请在“上解决” 实践 “首先，在讨论解决方案之前。

A. 简单解决方案 首先打印最大元素，然后打印最小元素，然后打印第二个最大元素，依此类推。该方法的时间复杂度为O（n） ^2. ). 一 有效解决方案 包括以下步骤。 1）使用O（n logn）算法对输入数组进行排序。 2）我们在排序数组中维护两个指针，一个从开始，一个从结束。我们也可以打印由两个指针指向的元素，并将它们相互移动。

C++

                         // C++ program to print an array in alternate                       
                         // sorted manner.                       
                         #include <bits/stdc++.h>                       
                         using                                     namespace                                     std;                       
           
                         // Function to print alternate sorted values                       
                         void                                     alternateSort(                                     int                                     arr[],                                     int                                     n)                       
                         {                       
                                                 // Sorting the array                       
                                                 sort(arr, arr+n);                       
           
                                                 // Printing the last element of array                       
                                                 // first and then first element and then                       
                                                 // second last element and then second                       
                                                 // element and so on.                       
                                                 int                                     i = 0, j = n-1;                       
                                                 while                                     (i < j) {                       
                                                 cout << arr[j--] <<                                     " "                                     ;                       
                                                 cout << arr[i++] <<                                     " "                                     ;                       
                                                 }                       
           
                                                 // If the total element in array is odd                       
                                                 // then print the last middle element.                       
                                                 if                                     (n % 2 != 0)                       
                                                 cout << arr[i];                       
                         }                       
           
                         // Driver code                       
                         int                                     main()                       
                         {                       
                                                 int                                     arr[] = {1, 12, 4, 6, 7, 10};                       
                                                 int                                     n =                                     sizeof                                     (arr)/                                     sizeof                                     (arr[0]);                       
                                                 alternateSort(arr, n);                       
                                                 return                                     0;                       
                         }                       

JAVA

                         // Java program to print an array in alternate                       
                         // sorted manner                       
                         import                                     java.io.*;                       
                         import                                     java.util.Arrays;                       
                                   
                         class                                     AlternativeString                       
                         {                       
                                                 // Function to print alternate sorted values                       
                                                 static                                     void                                     alternateSort(                                     int                                     arr[],                                     int                                     n)                       
                                                 {                       
                                                 Arrays.sort(arr);                       
           
                                                 // Printing the last element of array                       
                                                 // first and then first element and then                       
                                                 // second last element and then second                       
                                                 // element and so on.                       
                                                 int                                     i =                                     0                                     , j = n-                                     1                                     ;                       
                                                 while                                     (i < j) {                       
                                                 System.out.print(arr[j--] +                                     " "                                     );                       
                                                 System.out.print(arr[i++] +                                     " "                                     );                       
                                                 }                       
                                   
                                                 // If the total element in array is odd                       
                                                 // then print the last middle element.                       
                                                 if                                     (n %                                     2                                     !=                                     0                                     )                       
                                                 System.out.print(arr[i]);                       
                                                 }                       
           
                                                 /* Driver program to test above functions */                       
                                                 public                                     static                                     void                                     main (String[] args)                       
                                                 {                       
                                                 int                                     arr[] = {                                     1                                     ,                                     12                                     ,                                     4                                     ,                                     6                                     ,                                     7                                     ,                                     10                                     };                       
                                                 int                                     n = arr.length;                       
                                                 alternateSort(arr, n);                       
                                                 }                       
                         }                       
                         /*This code is contributed by Prakriti Gupta*/                       

Python3

                         # Python 3 program to print an array                       
                         # in alternate sorted manner.                       
           
                         # Function to print alternate sorted                       
                         # values                       
                         def                                     alternateSort(arr, n):                       
           
                                                 # Sorting the array                       
                                                 arr.sort()                       
           
                                                 # Printing the last element of array                       
                                                 # first and then first element and then                       
                                                 # second last element and then second                       
                                                 # element and so on.                       
                                                 i                                     =                                     0                       
                                                 j                                     =                                     n                                     -                                     1                       
                                   
                                                 while                                     (i < j):                       
                                   
                                                 print                                     (arr[j], end                                     =                                     " "                                     )                       
                                                 j                                     -                                     =                                     1                       
                                                 print                                     (arr[i], end                                     =                                     " "                                     )                       
                                                 i                                     +                                     =                                     1                       
           
                                                 # If the total element in array is odd                       
                                                 # then print the last middle element.                       
                                                 if                                     (n                                     %                                     2                                     !                                     =                                     0                                     ):                       
                                                 print                                     (arr[i])                       
           
           
                         # Driver code                       
                         arr                                     =                                     [                                     1                                     ,                                     12                                     ,                                     4                                     ,                                     6                                     ,                                     7                                     ,                                     10                                     ]                       
                         n                                     =                                     len                                     (arr)                       
           
                         alternateSort(arr, n)                       
           
                         # This code is contributed by                       
                         # Smitha Dinesh Semwal                       

C#

                         // C# program to print an array in alternate                       
                         // sorted manner                       
                         using                                     System;                       
           
                         class                                     AlternativeString {                       
                                   
                                                 // Function to print alternate sorted values                       
                                                 static                                     void                                     alternateSort(                                     int                                     [] arr,                                     int                                     n)                       
                                                 {                       
                                                 Array.Sort(arr);                       
           
                                                 // Printing the last element of array                       
                                                 // first and then first element and then                       
                                                 // second last element and then second                       
                                                 // element and so on.                       
                                                 int                                     i = 0, j = n - 1;                       
                                                 while                                     (i < j) {                       
                                                 Console.Write(arr[j--] +                                     " "                                     );                       
                                                 Console.Write(arr[i++] +                                     " "                                     );                       
                                                 }                       
           
                                                 // If the total element in array is odd                       
                                                 // then print the last middle element.                       
                                                 if                                     (n % 2 != 0)                       
                                                 Console.WriteLine(arr[i]);                       
                                                 }                       
           
                                                 /* Driver program to test above functions */                       
                                                 public                                     static                                     void                                     Main()                       
                                                 {                       
                                                 int                                     [] arr = { 1, 12, 4, 6, 7, 10 };                       
                                                 int                                     n = arr.Length;                       
                                                 alternateSort(arr, n);                       
                                                 }                       
                         }                       
           
                         // This article is contributed by vt_m.                       

PHP

                         <?php                       
                         // PHP program to print an array in                       
                         // alternate sorted manner.                       
           
                         // Function to print alternate                       
                         // sorted values                       
                         function                                     alternateSort(                                     $arr                                     ,                                     $n                                     )                       
                         {                       
                                                 // Sorting the array                       
                                                 sort(                                     $arr                                     );                       
           
                                                 // Printing the last element                       
                                                 // of array  first and then                       
                                                 // first element and then second                       
                                                 // last element and then second                       
                                                 // element and so on.                       
                                                 $i                                     = 0;                       
                                                 $j                                     =                                     $n                                     - 1;                       
                                                 while                                     (                                     $i                                     <                                     $j                                     )                       
                                                 {                       
                                                 echo                                     $arr                                     [                                     $j                                     --].                                     " "                                     ;                       
                                                 echo                                     $arr                                     [                                     $i                                     ++].                                     " "                                     ;                       
                                                 }                       
           
                                                 // If the total element in array                       
                                                 // is odd then print the last                       
                                                 // middle element.                       
                                                 if                                     (                                     $n                                     % 2 != 0)                       
                                                 echo                                     $arr                                     [                                     $i                                     ];                       
                         }                       
           
                         // Driver code                       
                         $arr                                     =                                     array                                     (1, 12, 4, 6, 7, 10);                       
                         $n                                     = sizeof(                                     $arr                                     ) / sizeof(                                     $arr                                     [0]);                       
           
                         alternateSort(                                     $arr                                     ,                                     $n                                     );                       
           
                         // This code is contributed by Mithun Kumar                       
                         ?>                       

Javascript

                         <script>                       
                                                 // JavaScript program to print an array in alternate                       
                                                 // sorted manner.                       
           
                                                 // Function to print alternate sorted values                       
                                                 function                                     alternateSort(arr, n)                       
                                                 {                       
                                   
                                                 // Sorting the array                       
                                                 console.log(arr);                       
                                                 arr.sort(                                     function                                     (a, b)                       
                                                 {                       
                                                 return                                     a - b;                       
                                                 });                       
                                                 console.log(arr);                       
           
                                                 // Printing the last element of array                       
                                                 // first and then first element and then                       
                                                 // second last element and then second                       
                                                 // element and so on.                       
                                                 var                                     i = 0,                       
                                                 j = n - 1;                       
                                                 while                                     (i < j)                       
                                                 {                       
                                                 document.write(arr[j--] +                                     " "                                     );                       
                                                 document.write(arr[i++] +                                     " "                                     );                       
                                                 }                       
           
                                                 // If the total element in array is odd                       
                                                 // then print the last middle element.                       
                                                 if                                     (n % 2 != 0) document.write(arr[i]);                       
                                                 }                       
           
                                                 // Driver code                       
                                                 var                                     arr = [1, 12, 4, 6, 7, 10];                       
                                                 var                                     n = arr.length;                       
                                                 alternateSort(arr, n);                       
                                   
                                                 // This code is contributed by rdtank.                       
                                                 </script>                       

输出：

12 1 10 4 7 6

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