Related Articles
Modify array by sorting nearest perfect squares of array elements having their digits sorted in decreasing order
• Last Updated : 16 Mar, 2021

Given an array arr[] of size N (1 ≤ N ≤ 105), the task is to sort digits of each array element in descending order and replace each array element with the nearest perfect square and then print the array in ascending order.

Examples:

Input: arr[ ] = {29, 43, 28, 12}
Output: 25 49 81 100
Explanation:
Sorting digits of each array element in descending order modifies arr[] to {92, 43, 82, 21}.
Replacing elements with the nearest perfect square modifies arr[] to {100, 49, 81, 25}.
Sorting the array in ascending order modifies arr[] to {25, 49, 81, 100}.

Input: arr[ ] = {517, 142, 905}
Output: 441 729 961

Approach: Follow the steps below to solve the problem:

Below is the implementation of the above approach.

## C++

 `// C++ program of the above approach` `#include ``using` `namespace` `std;` `// Function to sort array in ascending order``// after replacing array elements by nearest``// perfect square of decreasing order of digits``void` `sortArr(``int` `arr[], ``int` `N)``{` `    ``// Traverse the array of strings``    ``for` `(``int` `i = 0; i < N; i++) {` `        ``// Convert the current array``        ``// element to a string``        ``string s = to_string(arr[i]);` `        ``// Sort each string in descending order``        ``sort(s.begin(), s.end(), greater<``char``>());` `        ``// Convert the string to``        ``// equivalent integer``        ``arr[i] = stoi(s);` `        ``// Calculate square root of``        ``// current array element``        ``int` `sr = ``sqrt``(arr[i]);` `        ``// Calculate perfect square``        ``int` `a = sr * sr;``        ``int` `b = (sr + 1) * (sr + 1);` `        ``// Find the nearest perfect square``        ``if` `((arr[i] - a) < (b - arr[i]))``            ``arr[i] = a;``        ``else``            ``arr[i] = b;``    ``}` `    ``// Sort the array in ascending order``    ``sort(arr, arr + N);` `    ``// Print the array``    ``for` `(``int` `i = 0; i < N; i++) {``        ``cout << arr[i] << ``" "``;``    ``}``}` `// Driver Code``int` `main()``{``    ``int` `arr[] = { 29, 43, 28, 12 };``    ``int` `N = ``sizeof``(arr) / ``sizeof``(arr[0]);``    ``sortArr(arr, N);` `    ``return` `0;``}`

## Java

 `// Java program for the above approach``import` `java.util.*;` `class` `GFG{``  ``static` `void` `reverse(``char``[] a) ``  ``{``    ``int` `i, n = a.length;``    ``char` `t;``    ``for` `(i = ``0``; i < n / ``2``; i++) ``    ``{``      ``t = a[i];``      ``a[i] = a[n - i - ``1``];``      ``a[n - i - ``1``] = t;``    ``}``  ``}` `  ``// Function to sort array in ascending order``  ``// after replacing array elements by nearest``  ``// perfect square of decreasing order of digits``  ``static` `void` `sortArr(``int` `arr[], ``int` `N)``  ``{` `    ``// Traverse the array of strings``    ``for` `(``int` `i = ``0``; i < N; i++) {` `      ``// Convert the current array``      ``// element to a string``      ``String s = Integer.toString(arr[i]);``      ``char``[] str = s.toCharArray();` `      ``// Sort each string in descending order``      ``Arrays.sort(str);``      ``reverse(str);` `      ``String string = ``new` `String(str);`  `      ``// Convert the string to``      ``// equivalent integer``      ``arr[i] = Integer.parseInt(string);` `      ``// Calculate square root of``      ``// current array element``      ``int` `sr = (``int``)Math.sqrt(arr[i]);` `      ``// Calculate perfect square``      ``int` `a = sr * sr;``      ``int` `b = (sr + ``1``) * (sr + ``1``);` `      ``// Find the nearest perfect square``      ``if` `((arr[i] - a) < (b - arr[i]))``        ``arr[i] = a;``      ``else``        ``arr[i] = b;``    ``}` `    ``// Sort the array in ascending order``    ``Arrays.sort(arr);` `    ``// Print the array``    ``for` `(``int` `i = ``0``; i < N; i++) {``      ``System.out.print(arr[i] + ``" "``);``    ``}``  ``}`  `  ``// Driver Code``  ``public` `static` `void` `main(String[] args)``  ``{``    ``int` `arr[] = { ``29``, ``43``, ``28``, ``12` `};``    ``int` `N = arr.length;``    ``sortArr(arr, N);``  ``}``}` `// This code is contributed by sanjoy_62.`

## Python3

 `# Python 3 program of the above approach``import` `math` `# Function to sort array in ascending order``# after replacing array elements by nearest``# perfect square of decreasing order of digits``def` `sortArr(arr, N):` `    ``# Traverse the array of strings``    ``for` `i ``in` `range``(N):` `        ``# Convert the current array``        ``# element to a string``        ``s ``=` `str``(arr[i])` `        ``# Sort each string in descending order``        ``list1 ``=` `list``(s)``        ``list1.sort(reverse ``=` `True``)``        ``s ``=` `''.join(list1)` `        ``# Convert the string to``        ``# equivalent integer``        ``arr[i] ``=` `int``(s)` `        ``# Calculate square root of``        ``# current array element``        ``sr ``=` `int``(math.sqrt(arr[i]))` `        ``# Calculate perfect square``        ``a ``=` `sr ``*` `sr``        ``b ``=` `(sr ``+` `1``) ``*` `(sr ``+` `1``)` `        ``# Find the nearest perfect square``        ``if` `((arr[i] ``-` `a) < (b ``-` `arr[i])):``            ``arr[i] ``=` `a``        ``else``:``            ``arr[i] ``=` `b` `    ``# Sort the array in ascending order``    ``arr.sort()` `    ``# Print the array``    ``for` `i ``in` `range``(N):``        ``print``(arr[i], end``=``" "``)` `# Driver Code``if` `__name__ ``=``=` `"__main__"``:` `    ``arr ``=` `[``29``, ``43``, ``28``, ``12``]``    ``N ``=` `len``(arr)``    ``sortArr(arr, N)` `    ``# This code is contributed by ukasp.`

## C#

 `// C# program of the above approach` `using` `System;``using` `System.Collections.Generic;` `class` `GFG{` `  ``// Function to sort array in ascending order``  ``// after replacing array elements by nearest``  ``// perfect square of decreasing order of digits``  ``static` `void` `sortArr(``int` `[]arr, ``int` `N)``  ``{` `    ``// Traverse the array of strings``    ``for` `(``int` `i = 0; i < N; i++) {` `      ``// Convert the current array``      ``// element to a string``      ``int` `num = arr[i];``      ``string` `s = num.ToString();` `      ``// Sort each string in descending order``      ``char` `[]temp = s.ToCharArray();``      ``Array.Sort(temp);``      ``int` `st = 0;``      ``int` `ed = temp.Length-1;``      ``while``(st());` `      ``// Convert the string to``      ``// equivalent integer``      ``arr[i] = Int32.Parse(charsStr);` `      ``// Calculate square root of``      ``// current array element``      ``int` `sr = (``int``)Math.Sqrt(arr[i]);` `      ``// Calculate perfect square``      ``int` `a = sr * sr;``      ``int` `b = (sr + 1) * (sr + 1);` `      ``// Find the nearest perfect square``      ``if` `((arr[i] - a) < (b - arr[i]))``        ``arr[i] = a;``      ``else``        ``arr[i] = b;``    ``}` `    ``// Sort the array in ascending order``    ``Array.Sort(arr);` `    ``// Print the array``    ``for` `(``int` `i = 0; i < N; i++) {``      ``Console.Write(arr[i]+``" "``);``    ``}``  ``}` `  ``// Driver Code``  ``public` `static` `void` `Main()``  ``{``    ``int` `[]arr = { 29, 43, 28, 12 };``    ``int` `N = arr.Length;``    ``sortArr(arr, N);` `  ``}``}` `// This code is contributed by ipg2016107.`

Output:
`25 49 81 100`

Time Complexity: O(NlogN)
Auxiliary Space: O(1)

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.

My Personal Notes arrow_drop_up