Submission #1336877

#	Time	Username	Problem	Language	Result	Execution time	Memory
1336877		boclobanchat	Rack (eJOI19_rack)	C++20	100 / 100	4 ms	348 KiB

rack

#include<bits/stdc++.h>
using namespace std;
const long long mod=1e9+7;
const long long inv=5e8+4;
int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	long long n,k;
	cin>>n>>k;
	k--;
	long long p=1,ans=0;
	for(int i=1;i<n;i++) p=p*2%mod;
	while(k) ans=(ans+k%2*p)%mod,p=p*inv%mod,k/=2;
	cout<<(ans+1)%mod;
}

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