Find nCr Java

PROGRAM TO FIND nCr

class GFG {

  

// Function to find the nCr 

    static void printNcR(int n, int r) {

  

        // p holds the value of n*(n-1)*(n-2)..., 

        // k holds the value of r*(r-1)... 

        long p = 1, k = 1;

  

        // C(n, r) == C(n, n-r), 

        // choosing the smaller value 

        if (n - r < r) {

            r = n - r;

        }

  

        if (r != 0) {

            while (r > 0) {

                p *= n;

                k *= r;

  

                // gcd of p, k 

                long m = __gcd(p, k);

  

                // dividing by gcd, to simplify product 

                // division by their gcd saves from the overflow 

                p /= m;

                k /= m;

  

                n--;

                r--;

            }

  

            // k should be simplified to 1 

            // as C(n, r) is a natural number 

            // (denominator should be 1 ) . 

        } else {

            p = 1;

        }

  

        // if our approach is correct p = ans and k =1 

        System.out.println(p);

    }

  

    static long __gcd(long n1, long n2) {

        long gcd = 1;

  

        for (int i = 1; i <= n1 && i <= n2; ++i) {

            // Checks if i is factor of both integers

            if (n1 % i == 0 && n2 % i == 0) {

                gcd = i;

            }

        }

        return gcd;

    }

  

// Driver code 

    public static void main(String[] args) {

        int n = 50, r = 25;

  

        printNcR(n, r);

  

    }

}

OUTPUT

126410606437752

CREDITS: https://www.geeksforgeeks.org/program-to-calculate-the-value-of-ncr-efficiently/