题解 | 特殊乘法

#include <iostream>
#include<algorithm>
#include<vector>
#include<map>
#include<string>
#include<cstring>
using namespace std;
int main() {
	string n, m;
	while(cin >> n >> m){
	int sizen = n.size();
	int sizem = m.size();
	double mul=0;
	for (int i = 0; i < sizen; i++) {
		for (int j = 0; j < sizem; j++) {
			
			mul += (n[i] - '0') * (m[j] - '0');
		}
	}
	printf("%.0lf\n", mul);
	}
}