238. Product of Array Except Self

class Solution {
public:
    vector<int> productExceptSelf(vector<int>& nums) {
    	int n = nums.size();
        vector<int>pre(n, 1), post = pre, answer;

        for (int i = 1; i < n;i++) {
            pre[i] = pre[i - 1] * nums[i - 1];
        }
        for (int i = n - 2;i >= 0;i--) {
            post[i] = post[i + 1] * nums[i + 1];
        }

        for (int i = 0;i < n;i++) {
            answer.push_back(pre[i] * post[i]);
        }
        return answer;
    }
};