# A modified game of Nim

• Last Updated : 27 Apr, 2021

Given an array arr[] of integers, two players A and B are playing a game where A can remove any number of non-zero elements from the array that are multiples of 3. Similarly, B can remove multiples of 5. The player who can’t remove any element loses the game. The task is to find the winner of the game if A starts first and both play optimally.
Examples:

Input: arr[] = {1, 2, 3, 5, 6}
Output:
3 and 6 are the elements that A can remove.
5 is the only element that B can remove.
A can remove 3 in his first move then B will have to remove 5. In the next turn, A will remove 6 and B will be left with no more moves to make.
Input: arr[] = {3, 5, 15, 20, 6, 9}
Output:

Approach: Store the count of elements only divisible by 3 in movesA, count of elements only divisible by 5 in movesB and the elements divisible by both in movesBoth. Now,

• If movesBoth = 0 then both the players can remove only the elements which are divisible by their respective number and A will win the game only when movesA > movesB.
• If movesBoth > 0 then in order to play optimally, A will remove all the elements that are divisible by both 3 and 5 so that B is left with no elements to remove from the common elements then A will be the winner only if movesA + 1 > movesB

Below is the implementation of the above approach:

## C++

 `// C++ implementation of the approach``#include ``using` `namespace` `std;` `// Function to return the winner of the game``string getWinner(``int` `arr[], ``int` `n)``{``    ``int` `movesA = 0, movesB = 0, movesBoth = 0;` `    ``for` `(``int` `i = 0; i < n; i++) {` `        ``// Increment common moves``        ``if` `(arr[i] % 3 == 0 && arr[i] % 5 == 0)``            ``movesBoth++;` `        ``// Increment A's moves``        ``else` `if` `(arr[i] % 3 == 0)``            ``movesA++;` `        ``// Increment B's moves``        ``else` `if` `(arr[i] % 5 == 0)``            ``movesB++;``    ``}` `    ``// If there are no common moves``    ``if` `(movesBoth == 0) {``        ``if` `(movesA > movesB)``            ``return` `"A"``;``        ``return` `"B"``;``    ``}` `    ``// 1 is added because A can remove all the elements``    ``// that are part of the common moves in a single move``    ``if` `(movesA + 1 > movesB)``        ``return` `"A"``;``    ``return` `"B"``;``}` `// Driver code``int` `main()``{``    ``int` `arr[] = { 1, 2, 3, 5, 6 };``    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr);``    ``cout << getWinner(arr, n);` `    ``return` `0;``}`

## Java

 `// Java implementation of the approach``class` `GfG``{` `    ``// Function to return the winner of the game``    ``static` `String getWinner(``int` `arr[], ``int` `n)``    ``{``        ``int` `movesA = ``0``, movesB = ``0``, movesBoth = ``0``;``    ` `        ``for` `(``int` `i = ``0``; i < n; i++)``        ``{``    ` `            ``// Increment common moves``            ``if` `(arr[i] % ``3` `== ``0` `&& arr[i] % ``5` `== ``0``)``                ``movesBoth++;``    ` `            ``// Increment A's moves``            ``else` `if` `(arr[i] % ``3` `== ``0``)``                ``movesA++;``    ` `            ``// Increment B's moves``            ``else` `if` `(arr[i] % ``5` `== ``0``)``                ``movesB++;``        ``}``    ` `        ``// If there are no common moves``        ``if` `(movesBoth == ``0``)``        ``{``            ``if` `(movesA > movesB)``                ``return` `"A"``;``            ``return` `"B"``;``        ``}``    ` `        ``// 1 is added because A can remove``        ``// all the elements that are part``        ``// of the common moves in a single move``        ``if` `(movesA + ``1` `> movesB)``            ``return` `"A"``;``        ``return` `"B"``;``    ``}` `    ``// Driver code``    ``public` `static` `void` `main(String []args)``    ``{``        ` `        ``int` `arr[] = { ``1``, ``2``, ``3``, ``5``, ``6` `};``        ``int` `n = arr.length;``        ``System.out.println(getWinner(arr, n));``    ``}``}` `// This code is contributed by Rituraj Jain`

## Python3

 `# Python3 implementation of the approach` `# Function to return the winner of the game``def` `getWinner(arr, n):` `    ``movesA, movesB, movesBoth ``=` `0``, ``0``, ``0``    ``for` `i ``in` `range``(``0``, n):` `        ``# Increment common moves``        ``if` `arr[i] ``%` `3` `=``=` `0` `and` `arr[i] ``%` `5` `=``=` `0``:``            ``movesBoth ``+``=` `1` `        ``# Increment A's moves``        ``elif` `arr[i] ``%` `3` `=``=` `0``:``            ``movesA ``+``=` `1` `        ``# Increment B's moves``        ``elif` `arr[i] ``%` `5` `=``=` `0``:``            ``movesB ``+``=` `1` `    ``# If there are no common moves``    ``if` `movesBoth ``=``=` `0``:``        ``if` `movesA > movesB:``            ``return` `"A"``        ``return` `"B"` `    ``# 1 is added because A can``    ``# remove all the elements``    ``# that are part of the common``    ``# moves in a single move``    ``if` `movesA ``+` `1` `> movesB:``        ``return` `"A"``    ``return` `"B"` `# Driver code``if` `__name__ ``=``=` `"__main__"``:` `    ``arr ``=` `[``1``, ``2``, ``3``, ``5``, ``6``]``    ``n ``=` `len``(arr)``    ``print``(getWinner(arr, n))` `# This code is contributed by Rituraj Jain`

## C#

 `// C# implementation of the approach``using` `System;` `class` `GfG``{` `    ``// Function to return the winner of the game``    ``static` `String getWinner(``int` `[]arr, ``int` `n)``    ``{``        ``int` `movesA = 0, movesB = 0, movesBoth = 0;``    ` `        ``for` `(``int` `i = 0; i < n; i++)``        ``{``    ` `            ``// Increment common moves``            ``if` `(arr[i] % 3 == 0 && arr[i] % 5 == 0)``                ``movesBoth++;``    ` `            ``// Increment A's moves``            ``else` `if` `(arr[i] % 3 == 0)``                ``movesA++;``    ` `            ``// Increment B's moves``            ``else` `if` `(arr[i] % 5 == 0)``                ``movesB++;``        ``}``    ` `        ``// If there are no common moves``        ``if` `(movesBoth == 0)``        ``{``            ``if` `(movesA > movesB)``                ``return` `"A"``;``            ``return` `"B"``;``        ``}``    ` `        ``// 1 is added because A can remove``        ``// all the elements that are part``        ``// of the common moves in a single move``        ``if` `(movesA + 1 > movesB)``            ``return` `"A"``;``        ``return` `"B"``;``    ``}` `    ``// Driver code``    ``public` `static` `void` `Main(String []args)``    ``{``        ` `        ``int` `[]arr = { 1, 2, 3, 5, 6 };``        ``int` `n = arr.Length;``        ``Console.WriteLine(getWinner(arr, n));``    ``}``}` `// This code is contributed by``// Rajput-Ji`

## PHP

 ` ``\$movesB``)``            ``return` `"A"``;``        ``return` `"B"``;``    ``}` `    ``// 1 is added because A can remove all the elements``    ``// that are part of the common moves in a single move``    ``if` `(``\$movesA` `+ 1 > ``\$movesB``)``        ``return` `"A"``;``    ``return` `"B"``;``}` `    ``// Driver code``    ``\$arr` `= ``array``( 1, 2, 3, 5, 6 );``    ``\$n` `= sizeof(``\$arr``) / sizeof(``\$arr``);``    ``echo` `getWinner(``\$arr``, ``\$n``);` `// This code is contributed by ajit.``?>`

## Javascript

 ``

Output:

`A`

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