Submission #615987

#	Time	Username	Problem	Language	Result	Execution time	Memory
615987		kideso	Rack (eJOI19_rack)	C++17	100 / 100	10 ms	8148 KiB

rack

#include <iostream>
#include <queue>

using namespace std;
using ll = long long;

const ll maxN = 1e6, P = 1e9 + 7;

vector<ll> powers(maxN + 1);
ll N, K, ans;

void precomp(){
    powers[0] = 1;
    for(ll i = 1; i <= maxN; ++i)
        powers[i] = (powers[i - 1] * 2) % P;

    return;
}

int main(){
    precomp();
    
    cin >> N >> K;
    ans = 0;

    while(N != 0){
        if(K % 2 == 0) (ans += powers[N - 1]) %= P;
        --N;
        (K += 1) /= 2;
    }

    if(K == 1) (ans += 1) %= P;
    cout << ans << '\n';
    return 0;
}

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