Jianzhi offer Interview Question 66. Build a product array [simple]

Interview Question 66. Constructing a Product Array

class Solution {
public:
    vector<int> constructArr(vector<int>& a) {
        int n=a.size();
        vector<int> b(n,1);
        int tmp=1;
        for(int i=1;i<n;i++)
            b[i]=b[i-1]*a[i-1];
        for(int i=n-2;i>=0;i--){
            tmp*=a[i+1];
            b[i]*=tmp;
        }
        return b;
    }
};