Submission #774503

#	Time	Username	Problem	Language	Result	Execution time	Memory
774503		serifefedartar	Rack (eJOI19_rack)	C++17	100 / 100	7 ms	8152 KiB

rack

#include <bits/stdc++.h>

using namespace std;

#define fast ios::sync_with_stdio(0);cin.tie(0);
typedef long long ll;
#define mod 1000000007
#define MAXN 1000005

ll n, k;
ll pow2[MAXN];
int main() {
    fast
    pow2[0] = 1;
    for (ll i = 1; i < MAXN; i++)
        pow2[i] = (pow2[i-1] * 2) % mod;
    cin >> n >> k;

    ll ans = 1;
    for (ll i = 2; i < LLONG_MAX; i*=2) {
        if (k % i == 0 || k % i > i/2)
            ans = (ans + pow2[n-__builtin_ctzll(i)]) % mod;
        if (i > k)
            break;
    }
    cout << ans << endl;
}

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