Find nCrfor given n and r.
As answer can be very large, compute it modulo 109 + 7.
Example 1:
Input: n = 3, r = 2
Output: 3
Explanation: 3C2 = 3
​Example 2:
Input: n = 4, r = 2
Output: 6
Explanation: 4C2 = 6
Your Task:
You don't need to read input or print anything. Your task is to complete the function ncr() which takes n and r as inputs and returns the answer modulo 109 + 7.
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Avoid using static/global variables in your code as your code is tested
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On submission, your code is tested against multiple test cases consisting of all
possible corner cases and stress constraints.
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Avoid using static/global variables in coding problems as your code is tested
against multiple test cases and these tend to retain their previous values.
Passing the Sample/Custom Test cases in coding problems does not guarantee the
correctness of code. On submission, your code is tested against multiple test cases
consisting of all possible corner cases and stress constraints.
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