Submission #999812

#	Time	Username	Problem	Language	Result	Execution time	Memory
999812		hacizadal	Rack (eJOI19_rack)	C++17	100 / 100	2 ms	600 KiB

rack

/* :) */
#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define ll long long
#define pll pair<ll, ll>
#define mod 1000000007

ll power(ll x, ll y)
{
    if (y == 0) return 1;
    ll k = power(x, y/2);
    if (y%2==0){
        return (k*k)%mod;
    }
    else {
        return (((k*k)%mod)*x)%mod;
    }
}

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

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