Bittilista

import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Scanner;

public class Bittijono2 {

	static ArrayList<String> list = new ArrayList<>();
	static long n;
	static BigInteger k;

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		String input = scanner.nextLine();
		String[] split = input.split("\\s+");
		n = Long.parseLong(split[0]);
		k = new BigInteger(split[1]);

		BigInteger k2 = k.multiply(new BigInteger("2"));
		BigInteger power = new BigInteger((int) Math.pow(2, n - 1) + "");

		String formatString = "%" + n + "s";

		if (k2.compareTo(power) < 0) {
			String bitString = k2.subtract(new BigInteger("2")).toString(2);
			System.out.println(String.format(formatString, bitString).replace(' ', '0'));
		} else {
			String bitString = k2.subtract(new BigInteger("1")).toString(2);
			System.out.println(String.format(formatString, bitString).replace(' ', '0'));
		}
	}
}

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: WRONG ANSWER

Test 12

Group: 3

Verdict: WRONG ANSWER

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED