Submission #435556

#	Time	Username	Problem	Language	Result	Execution time	Memory
435556		Collypso	Counting Mushrooms (IOI20_mushrooms)	C++17	55.12 / 100	14 ms	388 KiB

mushrooms

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define pii pair<int, int>
#define pll pair<ll, ll>
#define vt vector
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int) (x).size()
#pragma GCC optimize ("O3")
#pragma GCC optimize ("O2")
#define F first
#define S second
//#define endl '\n'
//#define int long long

using namespace std;

int use_machine(vt<int> x);

int subtask1(int n)
{
	int ans = 1;
    for(int i = 1; i < n - 1; i += 2)
    {
        int tmp = use_machine({i + 1, 0, i});
        if (tmp == 0) ans += 2;
        else if (tmp == 1) ans += 1;
    }
    if (n % 2 == 0) ans += !use_machine({0, n - 1});
    return ans;
}

//if (n <= 452) return subtask1(n);

const int C = 80;

int count_mushrooms(int n)
{
    vt<int> v[2];
    v[0].pb(0);
    int q = 1, ans = 1;

    while(q < n && max(sz(v[0]), sz(v[1])) < C)
    {
        if (use_machine({0, q}) == 0) v[0].pb(q), ans++;
        else v[1].pb(q);
        q++;
    }

    int r = (sz(v[1]) > sz(v[0])) ? 1 : 0;
    int X = sz(v[r]);

    if (q >= n) return ans;

    for(int i = 0, to = (n - q + X - 2) / (X - 1); i < to; i++)
    {
        vt<int> tmp(1, v[r][0]);
        for(int j = 1; q < n && j < X; q++, j++)
            tmp.pb(q), tmp.pb(v[r][j]);
        if (r == 1) ans += use_machine(tmp) / 2;
        else ans += sz(tmp) / 2 - use_machine(tmp) / 2;
        //cout << ans << endl;
        //for(int x : tmp) cout << x << " ";
        //cout << endl;
        //cout << use_machine(tmp) << endl;
    }
    return ans;
}

• Subtask 1: 55.122 / 100