🟡 剑指 Offer 66. 构建乘积数组

LeetCode 提示

题目难度 中等

原题链接 🔗 leetcode

题解 1_愚昧的解法.py

class Solution:    def constructArr(self, a: List[int]) -> List[int]:        if not a:            return []        left, right = [1 for _ in range(len(a)+2)], [1 for _ in range(len(a)+2)]        length = len(a)        for idx, num in enumerate(a):            left[idx+1] = left[idx] * num            right[length-idx] = right[length-idx+1] * a[length-idx-1]                return [left[idx]*right[idx+2] for idx in range(len(a))]

题解 2_干练的解法.py

class Solution:    def constructArr(self, a: List[int]) -> List[int]:        b, tmp = [1 for _ in a], 1        for idx in range(1, len(a)):            b[idx] = b[idx-1] * a[idx-1]        for idx in range(len(a)-2, -1, -1):            tmp *= a[idx+1]            b[idx] *= tmp        return b