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# Number of times the largest perfect square number can be subtracted from N

• Difficulty Level : Basic
• Last Updated : 25 Mar, 2021

Given a number N. At every step, subtract the largest perfect square( ≤ N) from N. Repeat this step while N > 0. The task is to count the number of steps that can be performed.

Examples:

Input: N = 85
Output:
First step, 85 – (9 * 9) = 4
Second step 4 – (2 * 2) = 0

Input: N = 114
Output:
First step, 114 – (10 * 10) = 14
Second step 14 – (3 * 3) = 5
Third step 5 – (2 * 2) = 1
Fourth step 1 – (1 * 1) = 0

Approach: Iteratively subtract the largest perfect square (≤ N) from N while N > 0 and count the number of steps.
Below is the implementation of the above approach:

## C++

 `// C++ implementation of the approach``#include ``using` `namespace` `std;` `// Function to return the count of steps``int` `countSteps(``int` `n)``{` `    ``// Variable to store the count of steps``    ``int` `steps = 0;` `    ``// Iterate while N > 0``    ``while` `(n) {` `        ``// Get the largest perfect square``        ``// and subtract it from N``        ``int` `largest = ``sqrt``(n);``        ``n -= (largest * largest);` `        ``// Increment steps``        ``steps++;``    ``}` `    ``// Return the required count``    ``return` `steps;``}` `// Driver code``int` `main()``{``    ``int` `n = 85;``    ``cout << countSteps(n);` `    ``return` `0;``}`

## Java

 `// Java implementation of the approach``import` `java.lang.Math;` `public` `class` `GfG{` `    ``// Function to return the count of steps``    ``static` `int` `countSteps(``int` `n)``    ``{``        ``// Variable to store the count of steps``        ``int` `steps = ``0``;``    ` `        ``// Iterate while N > 0``        ``while` `(n > ``0``) {``    ` `            ``// Get the largest perfect square``            ``// and subtract it from N``            ``int` `largest = (``int``)Math.sqrt(n);``            ``n -= (largest * largest);``    ` `            ``// Increment steps``            ``steps++;``        ``}``    ` `        ``// Return the required count``        ``return` `steps;``    ``}` `     ``public` `static` `void` `main(String []args){``        ` `        ``int` `n = ``85``;``        ``System.out.println(countSteps(n));``     ``}``}` `// This code is contributed by Rituraj Jain`

## Python3

 `# Python3 implementation of the approach``from` `math ``import` `sqrt` `# Function to return the count of steps``def` `countSteps(n) :` `    ``# Variable to store the count of steps``    ``steps ``=` `0``;` `    ``# Iterate while N > 0``    ``while` `(n) :` `        ``# Get the largest perfect square``        ``# and subtract it from N``        ``largest ``=` `int``(sqrt(n));``        ``n ``-``=` `(largest ``*` `largest);` `        ``# Increment steps``        ``steps ``+``=` `1``;` `    ``# Return the required count``    ``return` `steps;``    ` `# Driver code``if` `__name__ ``=``=` `"__main__"` `:` `    ``n ``=` `85``;``    ``print``(countSteps(n));``    ` `# This code is contributed by Ryuga`

## C#

 `// C# implementation of the approach``using` `System;` `class` `GfG``{` `    ``// Function to return the count of steps``    ``static` `int` `countSteps(``int` `n)``    ``{``        ``// Variable to store the count of steps``        ``int` `steps = 0;``    ` `        ``// Iterate while N > 0``        ``while` `(n > 0)``        ``{``    ` `            ``// Get the largest perfect square``            ``// and subtract it from N``            ``int` `largest = (``int``)Math.Sqrt(n);``            ``n -= (largest * largest);``    ` `            ``// Increment steps``            ``steps++;``        ``}``    ` `        ``// Return the required count``        ``return` `steps;``    ``}` `    ``// Driver code``    ``public` `static` `void` `Main()``    ``{``        ``int` `n = 85;``        ``Console.WriteLine(countSteps(n));``    ``}``}` `// This code is contributed by Code_Mech.`

## PHP

 ` 0``    ``while` `(``\$n``)``    ``{` `        ``// Get the largest perfect square``        ``// and subtract it from N``        ``\$largest` `= (int)sqrt(``\$n``);``        ``\$n` `-= (``\$largest` `* ``\$largest``);` `        ``// Increment steps``        ``\$steps``++;``    ``}` `    ``// Return the required count``    ``return` `\$steps``;``}` `// Driver code``\$n` `= 85;``echo` `countSteps(``\$n``);` `// This code is contributed``// by Akanksha Rai``?>`

## Javascript

 ``
Output:
`2`

Time Complexity: O(1)

Auxiliary Space: O(1)

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