lintcode50 数组剔除元素后的乘积

class Solution {
public:
    /*
     * @param nums: Given an integers array A
     * @return: A long long array B and B[i]= A[0] * ... * A[i-1] * A[i+1] * ... * A[n-1]
     */
    vector<long long> productExcludeItself(vector<int> &nums) {
        // write your code here

        int len = nums.size();
        vector<long long> left(len, 1);
        vector<long long> right(len, 1);
        vector<long long> res(len, 1);

        for (int i = 1; i < len; ++i) {
            left[i] = left[i - 1] * nums[i - 1];
        }
        for (int i = len - 2; i >= 0; --i) {
            right[i] = right[i + 1] * nums[i + 1];
        }
        for(int i = 0; i < len; ++i) {
            res[i] = left[i] * right[i];
        }
        return res;
    }
};