# Find the number of ways to divide number into four parts such that a = c and b = d

Given a number N. Find the number of ways to divide a number into four parts(a, b, c, d) such that a = c and b = d and a not equal to b.

Examples:

Input : N = 6
Output : 1
Expalantion : four parts are {1, 2, 1, 2}

Input : N = 20
Output : 4
Expalantion : possible ways are {1, 1, 9, 9}, {2, 2, 8, 8}, {3, 3, 7, 7} and {4, 4, 6, 6}.

Approach :
If the given N is odd the answer is 0, because the sum of four parts will not be even number.

If n is divisible by 4 then answer will be n/4 -1(here a equals to b can be possible so subtract that possibility) otherwise n/4.

Below is the implementation of the above approach :

## C++

 `// C++ implementation for above approach ` `#include ` `using` `namespace` `std; ` ` `  `// Function to find the number of ways to divide ` `// N into four parts such that a = c and b = d ` `int` `possibleways(``int` `n) ` `{ ` `    ``if` `(n % 2 == 1) ` `        ``return` `0; ` `    ``else` `if` `(n % 4 == 0) ` `        ``return` `n / 4 - 1; ` `    ``else` `        ``return` `n / 4; ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``int` `n = 20; ` `    ``cout << possibleways(n); ` `    ``return` `0; ` `} `

## Java

 `// Java implementation for above approach ` `class` `GFG ` `{ ` `     `  `// Function to find the number of ways to divide ` `// N into four parts such that a = c and b = d ` `static` `int` `possibleways(``int` `n) ` `{ ` `    ``if` `(n % ``2` `== ``1``) ` `        ``return` `0``; ` `    ``else` `if` `(n % ``4` `== ``0``) ` `        ``return` `n / ``4` `- ``1``; ` `    ``else` `        ``return` `n / ``4``; ` `} ` ` `  `// Driver code ` `public` `static` `void` `main(String[] args) ` `{ ` `    ``int` `n = ``20``; ` `    ``System.out.println(possibleways(n)); ` `} ` `} ` ` `  `// This code contributed by Rajput-Ji `

## Python3

 `# Python3 implementation for above approach ` ` `  `# Function to find the number of ways  ` `# to divide N into four parts  ` `# such that a = c and b = d ` `def` `possibleways(n): ` ` `  `    ``if` `(n ``%` `2` `=``=` `1``): ` `        ``return` `0``; ` `    ``elif` `(n ``%` `4` `=``=` `0``): ` `        ``return` `n ``/``/` `4` `-` `1``; ` `    ``else``: ` `        ``return` `n ``/``/` `4``; ` ` `  `# Driver code ` `n ``=` `20``; ` `print``(possibleways(n)); ` ` `  `# This code is contributed by mits `

## C#

 `// C# implementation for above approach ` `class` `GFG ` `{ ` `     `  `// Function to find the number of ways to divide ` `// N into four parts such that a = c and b = d ` `static` `int` `possibleways(``int` `n) ` `{ ` `    ``if` `(n % 2 == 1) ` `        ``return` `0; ` `    ``else` `if` `(n % 4 == 0) ` `        ``return` `n / 4 - 1; ` `    ``else` `        ``return` `n / 4; ` `} ` ` `  `// Driver code ` `static` `void` `Main() ` `{ ` `    ``int` `n = 20; ` `    ``System.Console.WriteLine(possibleways(n)); ` `} ` `} ` ` `  `// This code is contributed by mits `

## PHP

 ` `

Output:

```4
```

My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.

Improved By : Mithun Kumar, Rajput-Ji, jit_t