Submission #1050836

#	Time	Username	Problem	Language	Result	Execution time	Memory
1050836		ThommyDB	Rack (eJOI19_rack)	C++17	40 / 100	1 ms	348 KiB

rack

#include<bits/stdc++.h>

using namespace std;

const int mod = 1e9+7;

int n, k;

signed main(){
    cin >> n >> k;

    vector<int> layers(n);

    layers[0]=1;
    signed long long s = 1;
    
    for(int i = 1; i < n; i++){
        s*=2;
        s%=mod;
        layers[i] = s;
    }

    long long ans = 1;
    for(int i = 0; i < n; i++){
        if(k%2==0){//right
            k /=2;
            ans += layers[n-i-1];
            ans%=mod;
        }
        else{//left
            k++;
            k /= 2;
        }
    }

    cout << ans << "\n";
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 0 / 60