# Sort perfect squares in an array at their relative positions

Given an integer array , 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

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

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++

 `// C++ program to sort all the elements that are ` `// perfect squares in their relative positions ` `#include ` `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); ` ` `  `    ``sortPerfectSquare(arr, n); ` ` `  `    ``return` `0; ` `} `

## Java

 `// 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 v1 = ``new` `Vector(); ` `    ``Vector v2 = ``new` `Vector(); ` ` `  `    ``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 `

## Python3

 `# 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 `

## 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<``int``> v1 = ``new` `List<``int``>(); ` `    ``List<``int``>v2 = ``new` `List<``int``>(); ` ` `  `    ``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 `

## PHP

 ` `

Output:

```9 44 64 81 21 100
```

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