제출 #465240

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
465240		Alen777	Rack (eJOI19_rack)	C++14	100 / 100	18 ms	15564 KiB

rack

#include <iostream>
#include <string>
#include <iomanip>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <cmath>
#include <algorithm>
#include <cstring>
using namespace std;

#define ll long long
#define ull unsigned ll
#define pb push_back
#define mpr make_pair
#define lb lower_bound
#define ld long double
#define ub upper_bound

ll n, k;
vector<ll> ast;
ll mod = 1e9 + 7;

ll rec(ll n, ll k) {
    if (n == 0) {
        return 1;
    } if (k % 2LL) {
        return rec(n - 1LL, (k + 1LL) / 2LL);
    }
    else {
        return (rec(n - 1LL, k / 2LL) + ast[n - 1]) % mod;
    }
}

void solve() {
    cin >> n >> k;
    vector<ll> x(n, 1);
    ast = x;
    for(int i = 1; i < n; i++) {
        ast[i] = (ast[i - 1] * 2) % mod;
    }
    cout << rec(n, k) << endl;
}

int main() {
    /*cout.setf(ios::fixed | ios::showpoint);
    cout.precision(6);*/
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
    solve();
    return 0;
}

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