Submission #467223

#	Time	Username	Problem	Language	Result	Execution time	Memory
467223		syrtin	Rack (eJOI19_rack)	C++17	100 / 100	5 ms	1228 KiB

rack

/*author:	syrtin*/
#include <bits/stdc++.h>

#define pb push_back
#define all(v) v.begin(),v.end()
#define ff first
#define ss second

using namespace std;

typedef long long ll;
typedef pair<long long, long long> pll;
typedef pair < int, int > pii;
typedef vector<int> vi;
typedef vector<long long> vll;

const int N = 1e6 + 1;
const ll MOD = 1e9 + 7;
const int inf = int(1e9);
const ll INF = ll(1e16);

bool j[N];
ll n, k;
void go() {
	if(k == 1)return;
	for(int i = 0; i < n; i++) {
		if((1ll << i) * 2 >= k) {
			k -= (1ll << i), j[n - 1 - i] = 1;
			go();
			return;
		}
	}
}
void SOLVE(/*WATLE*/) {
	cin >> n >> k;
	memset(j, 0, sizeof j);
	go();
	ll pl = 1, ans = 1;
	for(int o = 0; o < n; o++){
		if(j[o])ans += pl, ans %= MOD;
		pl *= 2;
		pl %= MOD;
	}
	cout << ans;
}

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
    int times = 1;
	//cin >> times;
    for(int i = 1; i <= times; i++) {
        //cout << "Case #" << t << ": ";
        SOLVE();
    }
    return 0;
}

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