Python | Leetcode Python题解之第528题按权重随机选择

题目：

题解：

class Solution:

    def __init__(self, w: List[int]):
        self.pre = list(accumulate(w))
        self.total = sum(w)

    def pickIndex(self) -> int:
        x = random.randint(1, self.total)
        return bisect_left(self.pre, x)