题目地址
Cutting an integer means to cut a K digits lone integer Z into two integers of (K/2) digits long integers A and B. For example, after cutting Z = 167334, we have A = 167 and B = 334. It is interesting to see that Z can be devided by the product of A and B, as 167334 / (167 × 334) = 3. Given an integer Z, you are supposed to test if it is such an integer.

Input Specification:
Each input file contains one test case. For each case, the first line gives a positive integer N (≤ 20). Then N lines follow, each gives an integer Z (10 ≤ Z <2
​31
​​ ). It is guaranteed that the number of digits of Z is an even number.

Output Specification:
For each case, print a single line Yes if it is such a number, or No if not.

Sample Input:
3
167334
2333
12345678

Sample Output:
Yes
No
No

#include <iostream>
#include <vector>
#include<algorithm>
#include <cmath>
#include<map>
#include<cstring>
#include<queue>
#include<string>
#include<set>
#include<stack>
using namespace std;
typedef long long ll;
const int maxn=100010,inf=100000000;
int n;string s;
int main(){
    cin>>n;
    while(n--){
        cin>>s;int len=s.length();
        ll a=stoll(s.substr(0,len/2)),b=stoll(s.substr(len/2)),c=stoll(s),d=a*b;
        if(d!=0&&c%d==0) cout<<"Yes"<<endl;         //太重要了，要先判断别让分母为0；
        else cout<<"No" <<endl;
    }
    return 0;
}