Submission #306931

#	Time	Username	Problem	Language	Result	Execution time	Memory
306931		ivan24	Counting Mushrooms (IOI20_mushrooms)	C++14	91.87 / 100	10 ms	588 KiB

mushrooms

#include "mushrooms.h"
#include <bits/stdc++.h>
using namespace std;

using ll = int;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef pair<ll,ll> ii;
typedef vector<ii> vii;
typedef vector<vii> vvii;
#define F first
#define S second

class Solver{
private:
    ll n;
    vi type, ctr;
    vvi byType;

    void add_type(ll x, bool t){
        if (n <= x || type[x] != -1) return;
        type[x] = t;
        byType[t].push_back(x);
        ctr[t]++;
    }

    void addOne(ll x){
        ll res = use_machine(vi{0,x});
        add_type(x,res);
    }

    void addTwo(ll x, ll y){
        //cout << x << " " << y << endl;
        bool t = 0;
        if (byType[0].size() < 2){
            t = 1;
        }
        //cout << t << " " << byType[t].size() << endl;
        ll res = use_machine(vi{x,byType[t][0],y,byType[t][1]});
        add_type(x,(res&1) ? !t : t);
        add_type(y,(res&2) ? !t : t);
    }
    bool big_query (){
        bool t = ((byType[0].size() > byType[1].size()) ? 0 : 1);
        ll min_idx = ctr[0]+ctr[1];
        ll max_idx = min((int)min_idx + (int)byType[t].size()-1,n-1);
        ll sz = max_idx-min_idx+1;
        if (min_idx >= n) return false;

        vi v;
        for (ll i = min_idx; max_idx >= i && n > i; i++){
            v.push_back(i);
            v.push_back(byType[t][i-min_idx]);
        }
        /*
        cout << min_idx << " - " << max_idx << endl;
        for (auto i: v) cout << i << " ";
        cout << endl;
        */
        ll res = use_machine(v);
        if (res%2 == 1){
            res--;
            add_type(min_idx,!t);
        }else add_type(min_idx,t);

        ctr[!t] += res/2;
        ctr[t] += sz-1-res/2;
        return true;
    }
public:
    Solver(ll n): n(n), type(n,-1), ctr(2,0), byType(2){
        type[0] = 0;
        ctr[0]++;
        byType[0].push_back(0);
    }

    int solve(){
        //cout << "hello\n";
        addOne(1);
        if (n > 2){
            addOne(2);
            for (ll i = 0; 100 > i && n > 2*i+4; i++){
                addTwo(2*i+3,2*i+4);
            }
            //cout << "hello\n";
            while(big_query()){}
        }
        return ctr[0];
    }
};

int count_mushrooms(int n) {
    Solver mySolver(n);
    return mySolver.solve();
}

• Subtask 1: 91.8699 / 100