Kyselyt

#include <iostream>
#include <vector>

using namespace std;

inline unsigned long long int pow(unsigned int base, unsigned long int exponent) {
	unsigned long long int r = 1;
	while (exponent--) r *= base;
	return r;
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);

	unsigned short int q;
	vector<unsigned long long int> kt;
	cin >> q;
	for (int i = 0; i < q; i++) {
		unsigned long long int tmp;
		cin >> tmp;
		kt.push_back(tmp);
	}

	for (unsigned int ki = 0; ki < kt.size(); ki++) {
		unsigned long long int k = kt[ki];
		if (k < 10) {
			cout << k << endl;
			continue;
		}
		k -= 10;
		unsigned long long int numbers = 90;
		for (unsigned long int n = 2; true; n++, numbers *= 10) {
			unsigned long long int uplimit = n * numbers;
			if (k < uplimit) {
				int j = k % n;
				if (j) cout << (k / (n * pow(10, n-1-j))) % 10 << endl;
				else cout << k / (n * pow(10, n-1)) + 1 << endl;
				break;
			}
			k -= uplimit;
		}
	}

	return 0;
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: ACCEPTED

Test 3

Group: 3

Verdict: ACCEPTED