Bittilista

#include <iostream>

using namespace std;
typedef long long ll;
int main(){
    ll n, k;
    cin >> n >> k;
    ll v;
    v=(k-1)*2;
    if(k > (ll)1<<(n-2)) ++v;
    ll a=1;
    string s;
    for(ll b=0; b<n; ++b){
        s+= (v & (a<<b))? "1":"0";
    }
    for(int i=n-1; i>=0; --i) cout << s[i];

}

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