Submission #242103

#	Time	Username	Problem	Language	Result	Execution time	Memory
242103		valerikk	Rack (eJOI19_rack)	C++17	100 / 100	6 ms	384 KiB

rack

#include<bits/stdc++.h>
using namespace std;

#define int long long 

const int M = 1e9 + 7;

int bin_pow(int val, int n){
    int res = 1;
    while(n > 0){
        if(n & 1){
            res *= val;
            res %= M;
        }
        val *= val;
        val %= M;
        n /= 2;
    }
    return res;
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, k;
    cin >> n >> k;
    k--;
    int ans = 1;
    for(int i = 0; i < n; i++){
        if(k & 1){
            ans += bin_pow(2, n - i - 1);
            ans %= M;
        }
        k /= 2;
    }
    cout << ans;
    return 0;
}

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