Submission #1308716

#	Time	Username	Problem	Language	Result	Execution time	Memory
1308716		maya_s	Rack (eJOI19_rack)	C++20	100 / 100	1 ms	576 KiB

rack

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod = (1e9 + 7);

ll power(ll a, ll b){
    if(b == 0) return 1;
    ll x = (power(a, b / 2));
    if(b % 2 == 0) return (x * x) % mod;
    return (((x * x) % mod) * a) % mod;
}

int main(){
    ios_base::sync_with_stdio(false); cin.tie(NULL);
    ll n, k; cin >> n >> k;
    ll x = 0, d = 2;
    for(ll i = 1; i <= 60; i++){
        ll d = (1ll << i);
        if(k % d > d / 2 || k % d == 0) x += power(2, n-i), x %= mod;
    }
    cout << (x+1) % mod;
}

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