力扣 随机数索引 Python

文章目录

• 题目
• 哈希表索引

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题目

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提示：参考力扣官方题解

哈希表索引

时间复杂度 O(n)

空间复杂度O(n)

from collections import defaultdict
from secrets import choice


class Solution:

    def __init__(self, nums: List[int]):
        self.pos = defaultdict(list)
        for i, num in enumerate(nums):
            self.pos[num].append(i)

    def pick(self, target: int) -> int:
        return choice(self.pos[target])


# Your Solution object will be instantiated and called as such:
# obj = Solution(nums)
# param_1 = obj.pick(target)