Kyselyt

#include <iostream>

using namespace std;
typedef long long longl;

longl power(longl x, longl e) {
    if (e == 0) return 1;
    if (e == 1) return x;
    return x * power(x,e-1);
}

int nthdigit(longl k) {
    longl n, x, p, m = 1;
    
    for(;;m++) {      
        if (k-(power(10,m))-1 < 0) break;
    }
    
    n = k - (power(10,m-1)-1);  
    p = n % m;
    
    if( p==0 ) {
        x = (power(10,m-1)) + (n/m);
        p = m;
    } else x = (power(10,m-1)) + (1+((n-1)/m));
    
    p = -(p-(m+1));
    return ((x % power(10,p))/(power(10,p-1)));
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    
    int q; longl k; cin >> q;
    for(;q>0; q--) {
        cin >> k;
        cout << nthdigit(k) << "\n";
    }
}

Test 1

Group: 1

Verdict: WRONG ANSWER

Test 2

Group: 2

Verdict: WRONG ANSWER

Test 3

Group: 3

Verdict: WRONG ANSWER