Submission #1515951

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Source Code Expand

from collections import defaultdict

class Combination:
    def __init__(self, mod):
        self.mod = mod
        self.fact = [1] * (2 * 10 ** 5 + 1)
        for i in range(1, 2 * 10 ** 5 + 1):
            self.fact[i] = i * self.fact[i - 1] % self.mod

    def nCr(self, n, k):
        a = self.fact[n] % self.mod
        b = (self.fact[k] * self.fact[n - k]) % self.mod
        c = pow(b, self.mod - 2, self.mod)
        return a * c % self.mod


def main():
    W, H = map(int, input().split())
    c = Combination(1000000007)
    print(c.nCr(W + H - 2, W - 1))


if __name__ == '__main__':
    main()

Submission Info

Judge Result