Submission #290152

#	Time	Username	Problem	Language	Result	Execution time	Memory
290152		sabamaku	Rack (eJOI19_rack)	C++14	100 / 100	1 ms	256 KiB

rack

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

long long n,m,cur;

long long MOD = 1e9 + 7;

long long solve(long long a,long long b){
    long long ans = 1;
    while(b){
        if(b % 2 == 1){
            ans = ans * a % MOD;
        }
        a = a * a % MOD;
        b /= 2;
    }
    return ans;
}

long long ans;

int main(){
    cin >> n >> m;
    cur = n - 1;
    while(m != 1){
        if(m % 2 == 0){
            ans = (ans + solve(2,cur)) % MOD;  
        }
        cur--;
        m -= m / 2;
    }
    cout << ans + 1 << endl;
}

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