Skip to content
Related Articles

Related Articles

Improve Article
Save Article
Like Article

Rearrange an array in order – smallest, largest, 2nd smallest, 2nd largest, ..

  • Difficulty Level : Easy
  • Last Updated : 29 Aug, 2021

Given an array of integers, task is to print the array in the order – smallest number, Largest number, 2nd smallest number, 2nd largest number, 3rd smallest number, 3rd largest number and so on…..
Examples: 
 

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

Input : arr[] = [1, 2, 3, 4]
Output :arr[] = {1, 4, 2, 3}

 

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.  To complete your preparation from learning a language to DS Algo and many more,  please refer Complete Interview Preparation Course.

In case you wish to attend live classes with experts, please refer DSA Live Classes for Working Professionals and Competitive Programming Live for Students.

A simple solution is to first find the smallest element, swap it with first element. Then find largest element, swap it with second element and so on. Time complexity of this solution is O(n2).
An efficient solution is to use sorting
1. Sort the elements of array. 
2. Take two variables say i and j and point them to the first and last index of the array respectively. 
3. Now run a loop and store the elements in the array one by one by incrementing i and decrementing j.
Let’s take an array with input 5, 8, 1, 4, 2, 9, 3, 7, 6 and sort them so the array become 1, 2, 3, 4, 5, 6, 7, 8, 9. Now take two variables say i and j and point them to the first and last index of the array respectively, run a loop and store value into new array by incrementing i and decrementing j. We get final result as 1 9 2 8 3 7 4 6 5. 
 

C++




// C++ program to print the array in given order
#include <bits/stdc++.h>
using namespace std;
 
// Function which arrange the array.
void rearrangeArray(int arr[], int n)
{  
    // Sorting the array elements
    sort(arr, arr + n);
 
    int tempArr[n];  // To store modified array
 
    // Adding numbers from sorted array to
    // new array accordingly
    int ArrIndex = 0;
 
    // Traverse from begin and end simultaneously
    for (int i = 0, j = n-1; i <= n / 2 ||
                    j > n / 2; i++, j--) {
        tempArr[ArrIndex] = arr[i];
        ArrIndex++;
        tempArr[ArrIndex] = arr[j];
        ArrIndex++;
    }
 
    // Modifying original array
    for (int i = 0; i < n; i++)
        arr[i] = tempArr[i];
}
 
// Driver Code
int main()
{
    int arr[] = { 5, 8, 1, 4, 2, 9, 3, 7, 6 };
    int n = sizeof(arr) / sizeof(arr[0]);
    rearrangeArray(arr, n);
 
    for (int i = 0; i < n; i++)
        cout << arr[i] << " ";
 
    return 0;
}


Java




// Java program to print the array in given order
import java.util.Arrays;
 
public class GFG {
 
    // Function which arrange the array.
    static void rearrangeArray(int arr[], int n)
    {  
        // Sorting the array elements
        Arrays.sort(arr);
      
        int[] tempArr = new int[n]; // To store modified array
         
        // Adding numbers from sorted array to
        // new array accordingly
        int ArrIndex = 0;
      
        // Traverse from begin and end simultaneously
        for (int i = 0, j = n-1; i <= n / 2 || j > n / 2;
                                           i++, j--) {
            if(ArrIndex < n)
            {
                tempArr[ArrIndex] = arr[i];
                ArrIndex++;
            }
             
            if(ArrIndex < n)
            {
                tempArr[ArrIndex] = arr[j];
                ArrIndex++;
            }
        }
      
        // Modifying original array
        for (int i = 0; i < n; i++)
            arr[i] = tempArr[i];
    }
      
    // Driver Code
    public static void main(String args[])
    {
        int arr[] = { 5, 8, 1, 4, 2, 9, 3, 7, 6 };
        int n = arr.length;
        rearrangeArray(arr, n);
      
        for (int i = 0; i < n; i++)
            System.out.print(arr[i]+" ");
    }
}
// This code is contributed by Sumit Ghosh


Python3




# Python 3 program to print
# the array in given order
 
# Function which arrange the
# array.
def rearrangeArray(arr, n) :
 
    # Sorting the array elements
    arr.sort()
 
    # To store modified array
    tempArr = [0] * (n + 1)
 
    # Adding numbers from sorted
    # array to new array accordingly
    ArrIndex = 0
 
    # Traverse from begin and end
    # simultaneously
    i = 0
    j = n-1
     
    while(i <= n // 2 or j > n // 2 ) :
     
        tempArr[ArrIndex] = arr[i]
        ArrIndex = ArrIndex + 1
        tempArr[ArrIndex] = arr[j]
        ArrIndex = ArrIndex + 1
        i = i + 1
        j = j - 1
     
    # Modifying original array
    for i in range(0, n) :
        arr[i] = tempArr[i]
         
 
# Driver Code
arr = [ 5, 8, 1, 4, 2, 9, 3, 7, 6 ]
n = len(arr)
rearrangeArray(arr, n)
 
for i in range(0, n) :
    print( arr[i], end = " ")
     
# This code is contributed by Nikita Tiwari.


C#




// C# program to print the
// array in given order
using System;
 
public class GFG {
 
    // Function which arrange the array.
    static void rearrangeArray(int []arr, int n)
    {
        // Sorting the array elements
        Array.Sort(arr);
     
        // To store modified array
        int []tempArr = new int[n];
         
        // Adding numbers from sorted array 
        // to new array accordingly
        int ArrIndex = 0;
     
        // Traverse from begin and end simultaneously
        for (int i = 0, j = n-1; i <= n / 2
             || j > n / 2; i++, j--) {
                                         
            if(ArrIndex < n)
            {
                tempArr[ArrIndex] = arr[i];
                ArrIndex++;
            }
             
            if(ArrIndex < n)
            {
                tempArr[ArrIndex] = arr[j];
                ArrIndex++;
            }
        }
     
        // Modifying original array
        for (int i = 0; i < n; i++)
            arr[i] = tempArr[i];
    }
     
    // Driver Code
    public static void Main(String []args)
    {
        int []arr = {5, 8, 1, 4, 2, 9, 3, 7, 6};
        int n = arr.Length;
        rearrangeArray(arr, n);
     
        for (int i = 0; i < n; i++)
        Console.Write(arr[i] + " ");
    }
}
 
// This code is contributed by Nitin Mittal.


PHP




<?php
// PHP program to print
// the array in given order
 
// Function which
// arrange the array.
function rearrangeArray($arr, $n)
{
    // Sorting the
    // array elements
    sort($arr);
 
    // To store modified array
    $tempArr = array($n);
     
    // Adding numbers from
    // sorted array to new
    // array accordingly
    $ArrIndex = 0;
 
    // Traverse from begin
    // and end simultaneously
    for ($i = 0, $j = $n - 1;
         $i <= $n / 2 || $j > $n / 2;
         $i++, $j--)
    {
        $tempArr[$ArrIndex] = $arr[$i];
        $ArrIndex++;
        $tempArr[$ArrIndex] = $arr[$j];
        $ArrIndex++;
    }
 
    // Modifying original array
    for ($i = 0; $i < $n; $i++)
        $arr[$i] = $tempArr[$i];
     
    for ($i = 0; $i < $n; $i++)
        echo $arr[$i] . " ";
}
 
// Driver Code
$arr = array(5, 8, 1, 4, 2,
             9, 3, 7, 6 );
$n = count($arr) ;
rearrangeArray($arr, $n);
 
// This code is contributed
// by Sam007
?>


Javascript




<script>
 
// Javascript program to prlet the
// array in given order
 
// Function which arrange the array.
function rearrangeArray(arr, n)
{
    // Sorting the array elements
    arr.sort();
 
    // To store modified array
    let tempArr = new Array(n);
     
    // Adding numbers from sorted array 
    // to new array accordingly
    let ArrIndex = 0;
 
    // Traverse from begin and end simultaneously
    for (let i = 0, j = n-1; i <= n / 2
         || j > n / 2; i++, j--) {
                                     
        if(ArrIndex < n)
        {
            tempArr[ArrIndex] = arr[i];
            ArrIndex++;
        }
         
        if(ArrIndex < n)
        {
            tempArr[ArrIndex] = arr[j];
            ArrIndex++;
        }
    }
 
    // Modifying original array
    for (let i = 0; i < n; i++)
        arr[i] = tempArr[i];
}
 
// Driver Code
 
let arr =[5, 8, 1, 4, 2, 9, 3, 7, 6]
let n = arr.length;
rearrangeArray(arr, n);
 
for (let i = 0; i < n; i++)
    document.write(arr[i] + " ");
 
 
</script>


Output: 

1 9 2 8 3 7 4 6 5

Time Complexity : O(n Log n) 
Auxiliary Space : O(n)
This article is contributed by Ayush Saxena. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
 




My Personal Notes arrow_drop_up
Recommended Articles
Page :