Bittilista

#include <bits/stdc++.h>
using namespace std;

#define g(x, j) (x & (1l << (j)))

int main()
{
	long n, k;
	cin >> n >> k;
	long o = 1l << (n - 1);
	if (!(n - 1)) {
		cout << k - 1 << endl;
	}
	else if (k <= o / 2) {
		--k;
		cout << 0;
		for (long j = n - 3; j >= 0; --j) {
			cout << !!g(k, j);
		}
		cout << 0;
	}
	else {
		cout << 1;
		k = k - 1 - o / 2;
		for (long j = n - 3; j >= 0; --j) {
			cout << !!g(k, j);
		}
		cout << 1;
	}
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED