def __init__(self):
        """
        \binom nk=\binom{n-1}{k-1}+\binom{n-1}k, \text{ for } 0<k<n,
        """
        self.C = [[1 for _ in xrange(2000)] for _ in xrange(2000)]
        for n in xrange(1, 2000):
            for k in xrange(1, n):  # 0<k<n
                self.C[n][k] = self.C[n - 1][k - 1] + self.C[n - 1][k]
dataset/ETHPy150Open algorhythms/HackerRankAlgorithms/K Candy Store.py/Solution.__init__/original