Sort perfect squares in an array at their relative positions

Given an integer array arr, the task is to sort only the elements which are perfect squares at their relative positions in the array (positions of other elements must not be affected).

Examples:

Input: arr[] = {2, 64, 9, 8, 1, 4}
Output: 2 1 4 8 9 64
1, 4, 9 and 64 are the only perfect squares from the array.

Input: arr[] = {1, 49, 2, 36}
Output: 1 36 2 49

Approach:

  • Initialize two empty vectors and traverse the array from left to right.
  • Take an integer and a float variable and for every element of the array store it’s square root in both of these variables.
  • If both the variables are equal then push the index of this element in the first vector and push the element itself in the second vector.
  • Sort the second vector.
  • Now, we have the index of all the required elements in the first vector and also all of the required elements in sorted order in the second vector.
  • So, insert the elements of the second vector into the array at the indices present in the first vector one by one.

Below is the implementation of the above approach:

C++

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// C++ program to sort all the elements that are
// perfect squares in their relative positions
#include <bits/stdc++.h>
using namespace std;
  
// function to sort all the elements that are
// perfect squares in their relative positions
void sortPerfectSquare(int arr[], int n)
{
    int a;
    float b;
  
    // v1 will contain index of perfect squares
    // v2 will contain each perfect square
    vector<int> v1;
    vector<int> v2;
  
    for (int i = 0; i < n; i++) {
        b = sqrt(arr[i]);
        a = b;
  
        // if both a and b are equal then
        // arr[i] is a perfect square
        if (a == b) {
            v1.push_back(i);
            v2.push_back(arr[i]);
        }
    }
  
    // sort second vector
    sort(v2.begin(), v2.end());
  
    // put the sorted perfect square
    // back into the array
    int j = 0;
    for (int i = 0; i < n; i++) {
        if (v1[j] == i) {
            arr[i] = v2[j];
            j++;
        }
    }
  
    // print final array
    for (int i = 0; i < n; i++)
        cout << arr[i] << " ";
}
  
// Driver code
int main()
{
    int arr[] = { 9, 44, 100, 81, 21, 64 };
    int n = sizeof(arr) / sizeof(arr[0]);
  
    sortPerfectSquare(arr, n);
  
    return 0;
}

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Java

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// Java program to sort all the elements that are 
// perfect squares in their relative positions 
import java.util.*;
  
class GFG
{
  
// function to sort all the elements that are 
// perfect squares in their relative positions 
static void sortPerfectSquare(int arr[], int n) 
    int a; 
    float b; 
  
    // v1 will contain index of perfect squares 
    // v2 will contain each perfect square 
    Vector<Integer> v1 = new Vector<Integer>();
    Vector<Integer> v2 = new Vector<Integer>();
  
    for (int i = 0; i < n; i++) 
    
        b = (float) Math.sqrt(arr[i]); 
        a = (int) b; 
  
        // if both a and b are equal then 
        // arr[i] is a perfect square 
        if (a == b)
        
            v1.add(i); 
            v2.add(arr[i]); 
        
    
  
    // sort second vector 
    Collections.sort(v2); 
  
    // put the sorted perfect square 
    // back into the array 
    int j = 0
    for (int i = 0; i < n; i++) 
    
        if (v1.get(j) == i) 
        
            arr[i] = v2.get(j); 
            j++; 
        
    
  
    // print final array 
    for (int i = 0; i < n; i++)
            System.out.print(arr[i]+" "); 
  
    // Driver code 
    public static void main(String[] args)
    {
        int arr[] = { 9, 44, 100, 81, 21, 64 }; 
        int n = arr.length; 
  
        sortPerfectSquare(arr, n);
    }
  
// This code is contributed by 29AjayKumar

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Python3

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# Python 3 program to sort all 
# the elements that are perfect 
# squares in their relative positions
  
# import sqrt() from math lib
from math import sqrt
  
# function to sort all the elements 
# that are perfect squares in their 
# relative positions 
def sortPerfectSquare(arr, n) :
      
    # v1 will contain index of 
    # perfect squares and v2 will 
    # contain each perfect square 
    v1 = []
    v2 = []
      
    for i in range(n):
        b = sqrt(arr[i])
        a = int(b)
          
        # if both a and b are equal then 
        # arr[i] is a perfect square 
        if a == b :
            v1.append(i)
            v2.append(arr[i])
      
    # sort second list 
    v2.sort()
      
    j = 0
      
    # put the sorted perfect square 
    # back into the array 
    for i in range(n) :
        if v1[j] == i :
            arr[i] = v2[j] 
            j += 1
      
    # print final array
    for i in range(n) :
        print(arr[i], end = " ")
          
# Driver code
if __name__ == "__main__" :
    arr = [9, 44, 100, 81, 21, 64]
    n = len(arr)
      
    sortPerfectSquare(arr, n); 
  
# This code is contributed by ANKITRAI1

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C#

// C# program to sort all the elements that are
// perfect squares in their relative positions
using System;
using System.Collections.Generic;

class GFG
{

// function to sort all the elements that are
// perfect squares in their relative positions
static void sortPerfectSquare(int []arr, int n)
{
int a;
float b;

// v1 will contain index of perfect squares
// v2 will contain each perfect square
List v1 = new List();
Listv2 = new List();

for (int i = 0; i < n; i++) { b = (float) Math.Sqrt(arr[i]); a = (int) b; // if both a and b are equal then // arr[i] is a perfect square if (a == b) { v1.Add(i); v2.Add(arr[i]); } } // sort second vector v2.Sort(); // put the sorted perfect square // back into the array int j = 0; for (int i = 0; i < n; i++) { if (v1[j] == i) { arr[i] = v2[j]; j++; } } // print final array for (int i = 0; i < n; i++) Console.Write(arr[i] + " "); } // Driver code public static void Main(String[] args) { int []arr = { 9, 44, 100, 81, 21, 64 }; int n = arr.Length; sortPerfectSquare(arr, n); } } // This code is contributed by // PrinciRaj1992 [tabby title = "PHP"]

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<?php
// PHP program to sort all the elements that are
// perfect squares in their relative positions
  
// function to sort all the elements that are
// perfect squares in their relative positions
function sortPerfectSquare($arr, $n)
{
    // v1 will contain index of perfect squares
    // v2 will contain each perfect square
    $v1 = array();
    $v2 = array();
  
    for ( $i = 0; $i < $n; $i++) 
    {
        $b = sqrt($arr[$i]);
        $a = (int)$b;
  
        // if both a and b are equal then
        // arr[i] is a perfect square
        if ($a == $b
        {
            array_push($v1, $i);
            array_push($v2, $arr[$i]);
        }
    }
  
    // sort second vector
    sort($v2);
  
    // put the sorted perfect square
    // back into the array
    $j = 0;
    for ( $i = 0; $i < $n; $i++) 
    {
        if ($v1[$j] == $i
        {
            $arr[$i] = $v2[$j];
            $j++;
        }
    }
  
    // print final array
    for ($i = 0; $i < $n; $i++)
        echo $arr[$i] . " ";
}
  
// Driver Code
$arr = array( 9, 44, 100, 81, 21, 64 );
$n = count($arr);
sortPerfectSquare($arr, $n);
  
// This code is contributed by Rajput-Ji
?>

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Output:

9 44 64 81 21 100


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