Source code for titan_pylib.math.comb


[docs]
 1class Comb:
 2
 3    def __init__(self, n: int) -> int:
 4        self.n = n + 1
 5        table = [[0] * self.n for _ in range(self.n)]
 6        for i in range(self.n):
 7            for j in range(i + 1):
 8                if j == 0 or j == i:
 9                    table[i][j] = 1
10                else:
11                    table[i][j] = table[i - 1][j - 1] + table[i - 1][j]
12        self.table = table
13

[docs]
14    def nCr(self, n: int, r: int) -> int:
15        return self.table[n][r]