Submission #805162

#	Time	Username	Problem	Language	Result	Execution time	Memory
805162		PixelCat	Counting Mushrooms (IOI20_mushrooms)	C++14	72.90 / 100	11 ms	512 KiB

mushrooms

#include "mushrooms.h"

#ifdef NYAOWO
#include "stub.cpp"
#endif

#include <bits/stdc++.h>
#define For(i, a, b) for(int i = a; i <= b; i++)
#define Forr(i, a, b) for(int i = a; i >= b; i--)
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define sz(x) ((int)x.size())
#define eb emplace_back
// #define int LL
using namespace std;
using i32 = int32_t;
using LL = long long;
using pii = pair<int, int>;

int SQ = 101;

int alter(vector<int> jury, vector<int> sus, bool flip) {
    assert(sz(jury) > sz(sus));
    vector<int> q;
    int n = sz(sus);
    q.eb(jury.back()); jury.pop_back();
    while(sz(sus)) {
        q.eb(sus.back()); sus.pop_back();
        q.eb(jury.back()); jury.pop_back();
    }
    int res = use_machine(q) / 2;
    if(flip) return res;
    return n - res;
}

bool check(int s0, int s1, int ss) {
    if(max(s0, s1) < 10) return true;
    int mxs;
    // dont ask?
    mxs = max(s0, s1) - 1;
    int cost0 = (ss + mxs - 1) / mxs;
    // ask?
    mxs = min(max(s0 + 1, s1 + 2), max(s0 + 2, s1 + 1));
    int cost1 = (ss - 3 + mxs - 1) / mxs + 2;
    return cost1 < cost0;
}

int count_mushrooms(int n) {
    if(n <= 227) {
        int ans = 1;
        For(i, 1, n - 1) {
            ans += 1 - use_machine({0, i});
        }
        return ans;
    }
    vector<int> v0(1, 0);
    vector<int> v1;
    vector<pii> oao;
    vector<int> sussy;
    Forr(i, n - 1, 1) sussy.eb(i);
    random_shuffle(all(sussy));
    while(check(sz(v0), sz(v1), sz(sussy))) {
        int a, b, c;
        a = sussy.back(); sussy.pop_back();
        b = sussy.back(); sussy.pop_back();
        c = sussy.back(); sussy.pop_back();
        int r1 = use_machine({0, a, b, c});
        if(r1 % 2) {
            v1.eb(c);
            if(r1 == 3) {
                v1.eb(a);
                v0.eb(b);
            } else {
                int r2 = use_machine({a, b, 0});
                (r2 == 1 ? v1 : v0).eb(a);
                (r2 == 0 ? v0 : v1).eb(b);
            }
        } else {
            v0.eb(c);
            if(r1 == 0) {
                v0.eb(a);
                v0.eb(b);
            } else {
                oao.eb(a, b);
            }
        }
    }
    if(!sz(v1)) {
        for(auto &i:oao) {
            sussy.eb(i.F);
            sussy.eb(i.S);
        }
    } else {
        int p = v1.back();
        for(auto &i:oao) {
            int r = use_machine({i.F, i.S, p});
            (r == 1 ? v0 : v1).eb(i.F);
            (r == 2 ? v0 : v1).eb(i.S);
        }
    }

    // for(auto &i:v0) cerr << i << " ";
    // cerr << "\n";
    // for(auto &i:v1) cerr << i << " ";
    // cerr << "\n";
    
    int ans = sz(v0);
    int flip = 0;
    if(sz(v0) < sz(v1)) {
        v0.swap(v1);
        flip = 1;
    }
    while(sz(sussy)) {
        int r = min(sz(sussy), sz(v0) - 1);
        vector<int> sus;
        For(i, 1, r) {
            sus.eb(sussy.back());
            sussy.pop_back();
        }
        ans += alter(v0, sus, flip);
    }
    return ans;
    // std::vector<int> m;
    // for (int i = 0; i < n; i++)
    // 	m.push_back(i);
    // int c1 = use_machine(m);
    // m = {0, 1};
    // int c2 = use_machine(m);
    // return c1+c2;
}

/*

3
0 1 1

4
0 1 0 0

*/

• Subtask 1: 72.9032 / 100