Submission #914857

#	Time	Username	Problem	Language	Result	Execution time	Memory
914857		sirnobody1456	Rack (eJOI19_rack)	C++14	100 / 100	4 ms	600 KiB

rack

// Source: https://usaco.guide/general/io

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

const int MOD = 1e9+7;

signed main() {
	int n, k;
	cin >> n >> k;

	int ans = 0;
	while(n--) {
		if (!(k&1)) {
			ans = (ans << 1)%MOD;
			ans++;
			k /= 2;
		} else {
			ans = (ans << 1)%MOD;
			 k= k/2 + 1;
		}
		
	}

	cout << (ans+1)%MOD << '\n';

	return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 60 / 60