Kyselyt

#include <iostream>
#include <cstdlib>
#include <sstream>

using namespace std;

unsigned long pow10(unsigned long x) {
    if (x == 0) {
        return 1;
    } else {
        return pow10(x - 1) * 10;
    }
}

int main() {
    char buffer[20];
    cin >> buffer;
    unsigned int count = atoi(buffer);

    for (unsigned int i = 0; i < count; i++) {
        cin >> buffer;
        unsigned long ordinal = atol(buffer);
        unsigned int magnitude = 0;

        while (ordinal > pow10(magnitude) * (magnitude + 1) * 9) {
            magnitude++;
            ordinal -= magnitude * pow10(magnitude - 1) * 9;
        }

        if (magnitude == 0) {
            cout << ordinal << endl;
            continue;
        }

        unsigned long value = pow10(magnitude) + (ordinal - 1) / (magnitude + 1);

        unsigned int thing = magnitude - (ordinal - 1) % (magnitude + 1);
        unsigned int digit = ((value % pow10(thing + 1)) - value % pow10(thing)) / pow10(thing);

        //cout << "value: " << value << endl; // These lines really came to handy when testing
        //cout << "magnitude: " << magnitude << endl;
        //cout << "ordinal: " << ordinal << endl;
        //cout << "thing: " << thing << endl;
        //cout << "top: " << ((value % pow10(thing + 1)) - value % pow10(thing)) << endl;
        //cout << "bottom: " << pow10(thing) << endl;

        cout << digit << endl;
    }

    return 0;
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: ACCEPTED

Test 3

Group: 3

Verdict: ACCEPTED