Find nCr Python

PROGRAM TO FIND nCr

from math import *

  

# Function to find the nCr

def printNcR(n, r):

  

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

    # k holds the value of r*(r-1)...

    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):

            p *= n

            k *= r

  

            # gcd of p, k

            m = gcd(p, k)

  

            # dividing by gcd, to simplify product

            # division by their gcd saves from the overflow

            p //= m

            k //= m

  

            n -= 1

            r -= 1

  

        # 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

    print(p)

  

# Driver code

if __name__ == "__main__":

    n = 50

    r = 25

  

    printNcR(n, r)







OUTPUT

126410606437752

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