Submission #467887

#	Time	Username	Problem	Language	Result	Execution time	Memory
467887		alontanay	Rack (eJOI19_rack)	C++14	100 / 100	5 ms	308 KiB

rack

#include <bits/stdc++.h>
#define ll long long
#define MOD 1000000007

using namespace std;

ll square(ll n) {
    return n*n;
}

ll pow2(ll n) {
    if(n == 0) { return 1; }
    return ((n%2)+1)*square(pow2(n/2));
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    ll n, k;
    cin >> n >> k;
    ll curr_pow = 1, total = 0;
    for( ; n > 60; n --) {
        curr_pow = (curr_pow*2)%MOD;
    }
    for(ll i = pow2(n-1); i > 0; i >>= 1) {
        if(i < k) {
            total = (total + curr_pow)%MOD;
            k -= i;
        }
        curr_pow = (curr_pow*2)%MOD;
    }
    cout << (total+1)%MOD << endl;
}

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