Submission #448354

#	Time	Username	Problem	Language	Result	Execution time	Memory
448354		mychecksedad	Rack (eJOI19_rack)	C++17	100 / 100	8 ms	316 KiB

rack

#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
#define MOD (1000000000+7)

ll fp(ll a, ll b){
    ll res = 1;
    while(b){
        if(b&1) (res*=a)%=MOD;
        (a*=a)%=MOD;
        b>>=1;
    }
    return res;
}


int main(){
    cin.tie(0); ios::sync_with_stdio(0);
    ll n, k, ans=1;
    cin >> n >> k;
    for(ll i = n-1; i >= 0; i--){
        if(k&1){
            k = (k>>1) + 1;
        }else{
            k >>= 1;
            ans += fp(2, i);
        }
        (ans%=MOD);
        (ans+=MOD)%=MOD;
    }
    cout << ans;
    return 0;
}

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