Submission #642360

#	Time	Username	Problem	Language	Result	Execution time	Memory
642360		AmirAli_H1	Rack (eJOI19_rack)	C++17	100 / 100	6 ms	7876 KiB

rack

// In the name of Allah

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

typedef long long int	ll;
typedef long double	ld;
typedef pair<int, int>	pii;
typedef pair<ll, ll>	pll;

#define all(x)		(x).begin(),(x).end()
#define len(x)		((ll) (x).size())
#define F		first
#define S		second
#define pb		push_back
#define sep             ' '
#define endl            '\n'
#define Mp		make_pair
#define kill(x)		cout << x << '\n', exit(0);
#define set_dec(x)	cout << fixed << setprecision(x);
#define file_io(x,y)	freopen(x, "r", stdin); freopen(y, "w", stdout);

const int mod = 1e9 + 7;

ll power(ll a, ll b) {
	if (b == 0) return 1;
	return power(a * a % mod, b / 2) * ((b & 1) ? a : 1) % mod;
}

int main() {
	ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	
	int n;
	ll k;
	cin >> n >> k;
	k -= 1;
	
	vector<ll> bt;
	for (int j = 0; j <= 60; j++) {
		if (k & (1ll << j)) bt.pb(1);
		else bt.pb(0);
	}
	bt.resize(n);
	reverse(all(bt));
	
	ll output = 1;
	for (int j = 0; j < n; j++) {
		if (bt[j] == 1) {
			output += power(2, j);
			output %= mod;
		}
	}
	cout << output << endl;
	
	return 0;
}

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