https://pintia.cn/problem-sets/994805260223102976/problems/1071785664454127616
#include <iostream>
#include <cmath>
using namespace std;
int main(){
int K, N, M, cnt = 0, tmpk;
cin >> M;
for(int i = 0; i < M; i++){
cin >> K;
tmpk = K, cnt = 0;
while(tmpk){
cnt++;
tmpk /= 10;
}
int j, tmp;
for(j = 1; j < 10; j++){
tmp = j*K*K;
if((tmp % (int)pow((double)10, (double)cnt)) == K)
break;
}
if(j < 10)
cout << j << " " << tmp << endl;
else
cout << "No\n";
}
return 0;
}