【238】除自身以外数组的乘积：中等

https://leetcode-cn.com/problems/product-of-array-except-self/ 数组

暴力破解

function productExceptSelf(nums: number[]): number[] {
    function getLeft(k) {
        let left = 1
        for (let i = 0; i < k; i++) {
            left = left * nums[i]
        }
        return left
    }
    function getRight(k) {
        let right = 1
        for (let i = k + 1; i < nums.length; i++) {
            right = right * nums[i]
        }
        return right
    }
    const res = []
    nums.map((item, index) => {
        res.push(getLeft(index) * getRight(index))
    })
    return res
};

正反遍历

function productExceptSelf(nums: number[]): number[] {
    const res = []

    for (let i = 0, temp = 1; i < nums.length; i++) {
        res[i] = temp
        temp *= nums[i]
    }

    for (let i = nums.length - 1, temp = 1; i >= 0; i--) {
        res[i] *= temp
        temp *= nums[i]
    }

    return res
};