Submission #448542

#	Time	Username	Problem	Language	Result	Execution time	Memory
448542		Tenis0206	Rack (eJOI19_rack)	C++11	100 / 100	8 ms	7816 KiB

rack

#include <bits/stdc++.h>

using namespace std;
const int Mod = 1e9+7;
int n;
long long k,p[1000005];
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin>>n>>k;
    p[0] = 1;
    for(int i=1;i<=n;i++)
    {
        p[i] = 1LL*p[i-1]*2%Mod;
    }
    long long rez = 1;
    while(k!=1)
    {
        if(k%2==0)
        {
            rez+=p[n-1];
            rez%=Mod;
        }
        k = (k+1)/2;
        --n;
    }
    cout<<rez<<'\n';
    return 0;
}

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