class Solution {
public:
    vector<int> productExceptSelf(vector<int>& nums) {
        int n=nums.size();
        vector<int> fromBegin(n);
        fromBegin[0]=1;
        vector<int> fromLast(n);
        fromLast[0]=1;

        for(int i=1;i<n;i++){
            fromBegin[i]=fromBegin[i-1]* nums[i-1];
            fromLast[i]=fromLast[i-1]* nums[n-i];
        }

        vector<int> res(n);
        for(int i=0;i<n;i++){
            res[i]=fromBegin[i]* fromLast[n-1-i];
        }
        return res;
    }
};