Bittilista

#include <bits/stdc++.h>

#define i64 long long
#define u64 unsigned long long
#define i32 int
#define u32 unsigned int

#define pii pair<int, int>
#define pll pair<long long, long long>

#define defmod 1000000007
using namespace std;
int n, k;
vector<int> lol;
bool d[2<<21] = {0};

void hae(int i){
	if(d[i])
		return;
	d[i] = true;
	int ok = (i&1) + ((i&(1<<(n-1))) > 0);
	//cout << ok<<" " << bitset<7>(i) << endl;
	if(ok != 1){
		lol.push_back(i);
		//cout << "lisataan " << bitset<7>(i) << endl;
	}
	for(int j = 0; j < n; j++){
		hae(i|(1<<j));
	}

}
int main(){
	cin.sync_with_stdio(0);
	cin.tie(0);
	cin >> n >> k;
	hae(0);
	sort(lol.begin(), lol.end());
	int i = lol[k-1];
	for(int j = n-1; j >= 0; j--){
		if(i&(1<<j))
			cout << "1";
		else
			cout << "0";

	}
	cout << endl;
	return 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: RUNTIME ERROR

Test 12

Group: 3

Verdict: RUNTIME ERROR

Test 13

Group: 3

Verdict: RUNTIME ERROR

Test 14

Group: 3

Verdict: RUNTIME ERROR

Test 15

Group: 3

Verdict: RUNTIME ERROR