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Sum of all the numbers present at given level in Modified Pascal’s triangle
• Last Updated : 07 Apr, 2021

Given a level N, the task is to find the sum of all the integers present at this given level in an Alternating Pascal’s triangle.
An Modified Pascal triangle with 5 levels is as shown below.

```     1
-1 1
1 -2 1
-1 3 -3 1
1 -4 6 -4 1```

Examples:

```Input: N = 1
Output: 1

Input: N = 2
Output: 0```

Approach: As we can observe that for even level sum is 0 and for odd level except for 1 sum is also 0. So There can be at most 2 cases:

• If L = 1, then answer is 1.
• Otherwise the answer will always be 0.

Below is the implementation of the above approach:

## C++

 `// C++ program to calculate sum of``// all the numbers present at given``// level in an Modified Pascal’s triangle` `#include ``using` `namespace` `std;` `// Function to calculate sum``void` `ans(``int` `n)``{``    ``if` `(n == 1)``        ``cout << ``"1"``;``    ``else``        ``cout << ``"0"``;``}` `// Driver Code``int` `main()``{``    ``int` `n = 2;``    ``ans(n);` `    ``return` `0;``}`

## Java

 `// Java program to calculate sum of``// all the numbers present at given``// level in an Modified Pascal's triangle``class` `GFG``{` `// Function to calculate sum``static` `void` `ans(``int` `n)``{``    ``if` `(n == ``1``)``        ``System.out.println(``"1"``);``    ``else``        ``System.out.println(``"0"``);``}` `// Driver Code``public` `static` `void` `main(String[] args)``{``    ``int` `n = ``2``;``    ``ans(n);``}``}` `// This code is contributed by 29AjayKumar`

## Python3

 `# Python3 program to calculate sum of``# all the numbers present at given``# level in an Modified Pascal’s triangle` `# Function to calculate sum``def` `ans(n) :` `    ``if` `(n ``=``=` `1``) :``        ``print``(``"1"``,end``=``"");``    ``else` `:``        ``print``(``"0"``,end``=``"");` `# Driver Code``if` `__name__ ``=``=` `"__main__"` `:` `    ``n ``=` `2``;``    ``ans(n);``    ` `# This code is contributed by AnkitRai01`

## C#

 `// C# program to calculate sum of``// all the numbers present at given``// level in an Modified Pascal's triangle``using` `System;``    ` `class` `GFG``{` `// Function to calculate sum``static` `void` `ans(``int` `n)``{``    ``if` `(n == 1)``        ``Console.WriteLine(``"1"``);``    ``else``        ``Console.WriteLine(``"0"``);``}` `// Driver Code``public` `static` `void` `Main(String[] args)``{``    ``int` `n = 2;``    ``ans(n);``}``}` `// This code is contributed by 29AjayKumar`

## Javascript

 ``
Output:
`0`

Time Complexity: O(1)

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