Maximum Handshakes
Basic Accuracy: 51.13% Submissions: 278 Points: 1

There are N people in a room. If two persons shake hands exactly once, find the maximum number of handshakes possible. 

 

Example 1:

Input: N = 2
Output: 1
Explaination: There are two people and they 
can shake hands maximum one time.

 

Example 2:

Input: N = 3
Output: 3
Explaination: Let the people be person 1, 2 and 3. 
So the possible handshakes are (1, 2), (2, 3) and 
(1, 3).

 

Your Task:
You do not need to read input or print anything. Your task is to complete the function handShakes() which takes N as input parameter and returns the maximum number of handshakes possible.

 

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

 

Constraints:
2 ≤ N ≤ 109

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Maximum Handshakes

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