Maximum number of handshakes

March 16, 2021

Java program for finding Maximum number of handshakes

The given program will find the maximum number of handshakes in a room. Suppose there are N persons in a room. We have to find the maximum number of Handshakes possible. Given the fact that any two persons shake hand only once.

Example:

N=3

namely A,B,C

A shakes hand with B and C. now B shakes hand with C.Thus total number of ways to shake hands are 2+1 = 3 ways . 

java program for finding the maximum number of handshakes

Explanation:

Suppose  you entered into a room and there are N numbers of people .You shake hand with your friend so now you have N-1 people left to shake hands with . Similarly for your friend there are N-2 people left and so on.

Thus the above problem can be solved by simple nC2 .

Implementation

  •  Start
  •  user is asked to input an integer value n, representing the number of people
  •  calculate answer as  n * (n – 1) / 2 as explained earlier .

    Example: 

    n=3 

    3*(3-1)/2=3 

    thus 3 ways.

  •  Print the output from the above program

  •  End

Code in Java:

// Java program to find maximum number of handshakes
import java.io.*;
import java.util.*;

class handshakes
{ 
    // Calculating the maximum number of handshakes 
    static int maxHandshake(int n) 
    { 
        return (n * (n – 1)) / 2; 
    } 
    
    
    // Driver code 
    public static void main (String[] args) 
    { 
        Scanner sc=newScanner(System.in);
        int n = sc.nextLine(); 
        System.out.println( maxHandshake(n)); 
    } 
} 


output:

20

190