Submission #446733

#	Time	Username	Problem	Language	Result	Execution time	Memory
446733		BT21tata	Rack (eJOI19_rack)	C++17	100 / 100	1 ms	204 KiB

rack

#include<bits/stdc++.h>
// #pragma GCC target ("avx,avx2,fma")
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
typedef long long ll;
typedef long double ld;
#define SPEED ios_base::sync_with_stdio(false); cin.tie(0), cout.tie(0)
#define rall(v) (v).rbegin(),(v).rend()
#define all(v) (v).begin(),(v).end()
#define OK cerr<<"OK"<<endl<<flush
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define F first
#define S second
#define y0 jahdakdh
#define y1 jahsadakdakdh
#define endl '\n'
using namespace std;
const ll MOD=1e9+7;
// mt19937 rng(std::chrono::system_clock::now().time_since_epoch().count());

ll pw(ll b, ll p)
{
    if(!p) return 1;
    ll P=pw(b, p>>1);
    if(p&1) return P*P%MOD*b%MOD;
    return P*P%MOD;
}

ll f(ll n, ll k)
{
    if(k==1) return 1;
    if(k&1) return f(n-1, (k+1)>>1);
    return f(n, k-1)+pw(2, n-1);
}

int main()
{
    SPEED;
    ll n, k;
    cin>>n>>k;
    cout<<f(n, k)%MOD;
    return 0;
}

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