LeetCode 238 计算数组除自己外的元素乘积

class Solution {public:    vector<int> productExceptSelf(vector<int>& nums) {        int n = nums.size();        vector<int> res(n, 1); // res有n个元素，值为1        if(n <= 1){            return nums;        }        for(int i = 1; i < n; i++){ // res={1, n0, n0n1, n0n1n2};            res[i] = res[i-1] * nums[i-1];        }        int right = 1;        for(int i = n-2; i >= 0; i--){            right *= nums[i+1]; // right = n3,n3n2,n3n2n1            res[i] = res[i]*right;        }        return res;    }};