Submission #809121

#	Time	Username	Problem	Language	Result	Execution time	Memory
809121		ThylOne	Rack (eJOI19_rack)	C++14	100 / 100	9 ms	7892 KiB

rack

#include<bits/stdc++.h>

using namespace std;
const int MOD = 1000000007;
signed main(){
	long long n,k;cin>>n>>k;
	k--;
	long long ans=1;
	long long add=n;
	vector<long long > power(n+2);
	power[0]=1;
	for(int i =1;i<=n;i++){
		power[i] = 2*power[i-1]%MOD;
	}
	for(int i=0;i<n;i++){
		add--;
		if((k)&1){
			//right
		ans +=power[add];
		ans%=MOD;
		}
		k/=2;
		
	}
	cout<<ans%MOD<<endl;
}

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