BinomialCoefficient.java

package com.interview.number;

/**
 * http://www.geeksforgeeks.org/space-and-time-efficient-binomial-coefficient/
 * Test cases
 * k is 0
 * k or n are negative
 * k greater than n
 */
public class BinomialCoefficient {

    public int calculate(int n, int k){
        if(k > n-k){
            k = n-k;
        }
        int result = 1;
        for(int i=0; i < k; i++){
            result *= (n-i);
            result /= (i+1);
        }
        return result;
    }
    
    public static void main(String args[]){
        BinomialCoefficient bc = new BinomialCoefficient();
        System.out.print(bc.calculate(8, 3));
    }
}