【解決方法】この課題を解決するにはどうすればよいですか

Given a natural number k (1≤k≤18), we need to find the smallest square number with k digits, where each digit is also a square number.

Input:

The number of test cases t (0<t<10^3).
For each test case, input a natural number k.
Output:

Each line corresponds to a test case and prints the found number. If no number is found, print -1.
Example:
Input:
2
1
3

Output:
1
100

私が試したこと:

#include<iostream>
#include<cmath>
using namespace std;

int scp(int n){
    int can = sqrt(n);
    if (can * can == n)
        return 1;
    else
        return 0;
}

long long find(int k){
    if (k > 18){
        return -1;
    }

    long long socantim = 0;
    for (int i = 0; i < k; i++){
        int khoitao = 1;
        while (!scp(khoitao)){
            khoitao++;
        }
        socantim = socantim * 10 + khoitao;
    }

    if (socantim == 0){
        return -1;
    }

    return socantim;
}

int main(){
    int t;
    cin >> t;
    while (t--){
        int a;
        cin >> a;
        cout << find(a) << endl;
    }
    return 0;
}