Medium Accuracy: 32.71% Submissions: 55515 Points: 4

Given two integers n and r, find nCr. Since the answer may be very large, calculate the answer modulo 109+7.

Example 1:

Input: n = 3, r = 2
Output: 3
Explaination: 3C2 = 3. 

Example 2:

Input: n = 2, r = 4
Output: 0
Explaination: r is greater than n.

Your Task:
You do not need to take input or print anything. Your task is to complete the function nCr() which takes n and r as input parameters and returns nCmodulo 109+7..

Expected Time Complexity: O(n*r)
Expected Auxiliary Space: O(r)

1 ≤ n ≤ 1000
1 ≤ r ≤ 800

We are replacing the old Disqus forum with the new Discussions section given below.
Click here to view old Disqus comments.

to report an issue on this page.


We strongly recommend solving this problem on your own before viewing its editorial. Do you still want to view the editorial?


All Submissions

My Submissions:

Login to access your submissions.


Output Window