Submission #334813

#	Time	Username	Problem	Language	Result	Execution time	Memory
334813		limabeans	Rack (eJOI19_rack)	C++17	100 / 100	5 ms	384 KiB

rack

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

template<typename T>
void out(T x) { cout << x << endl; exit(0); }
#define watch(x) cout << (#x) << " is " << (x) << endl





using ll = long long;

const ll mod = 1e9+7;


ll f(ll n, ll k) {
    if (n==0) return 1;
    if (n<=62 && k>(1ll<<n)/2) {
	return 2ll*f(n-1,k-(1ll<<n)/2);
    } else {
	return 2ll*f(n-1,k)-1;
    }
}


int main() {
    ios_base::sync_with_stdio(false); cin.tie(0);  cout.tie(0);

    ll n,k;
    cin>>n>>k;

    ll res = 0;
    --k;
    for (int i=0; i<n; i++) {
	res=2ll*res%mod+(k%2)%mod;
	k /= 2;
    }

    res++;
    res %= mod;
    res += mod;
    res %= mod;

    cout<<res;
    return 0;
}

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