Submission #894290

#	Time	Username	Problem	Language	Result	Execution time	Memory
894290		vjudge1	Rack (eJOI19_rack)	C++17	100 / 100	348 ms	756 KiB

rack

#include<bits/stdc++.h>

using namespace std;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef long long ll;
#define int ll
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define pb push_back
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
#define mispertion ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define F first
#define S second
#define getlast(s) (*s.rbegin())
#define debg cout << "OK\n"

const ld PI = 3.1415926535;
const int N = 5e3 + 2;
const int M = 7e6 + 1;
int mod = 1e9+7;
const int infi = INT_MAX;
const ll infl = LLONG_MAX;
const int P = 31;

int mult(int a, int b) {
    return a * 1LL * b % mod;
}

int sum(int a, int b) {
    a %= mod; 
    if (a + b < 0)
        return a + b + mod;
    if (a + b >= mod)
        return a + b - mod;
    return a + b;
}

ll binpow(ll a, ll n) {
    if (n == 0)
        return 1;
    if (n % 2 == 1) {
        return binpow(a, n - 1) * a % mod;
    } else {
        ll b = binpow(a, n / 2);
        return b * b % mod;
    }
}


int getans(int i, int l, int r, int cur, int n){
    if(i == n)
        return l;
    int m = mult(sum(r, sum(l, -1)), binpow(2, mod - 2));
    if(cur % 2 == 0)
        return getans(i + 1, l, m, cur / 2, n);
    else
        return getans(i + 1, sum(m, 1), r, cur / 2, n);
}

void solve(){
    int n;
    cin >> n;
    int k = 1;
    cin >> k;
    cout << getans(0, 1, binpow(2, n), k - 1, n);
}   

signed main() {
    mispertion;
    int t = 1;
    //cin >> t;
    while(t--){
        solve();
    }
    return 0;
}

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