Submission #307864

#	Time	Username	Problem	Language	Result	Execution time	Memory
307864		Vimmer	Counting Mushrooms (IOI20_mushrooms)	C++14	0 / 100	5 ms	384 KiB

mushrooms

#include <bits/stdc++.h>
#include "mushrooms.h"
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>

#define N 100005
#define PB push_back
#define sz(x) int(x.size())
#define F first
#define M ll(1e9 + 7)
#define S second
#define all(x) x.begin(), x.end()
#define endl '\n'

//#pragma GCC optimize("unroll-loops")
//#pragma GCC optimize("-O3")
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("fast-math")
//#pragma GCC optimize("no-stack-protector")

using namespace std;
//using namespace __gnu_pbds;

typedef long long ll;
//typedef tree <int, null_type, less_equal <int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

int ask(vector <int> &m) { return use_machine(m);}
int ask(set <int> &se) {vector <int> m; m.clear(); for (auto it : se) m.PB(it); return use_machine(m);}

ll mlt(ll x, ll y) {return (x * y) % M;}
ll sm(ll x, ll y) {return (x + y) % M;}

int NEED = 20, bad, nr;

vector <int> tr;

int es_minus_3(vector <int> &pr, set <int> &se)
{
    int ans = sz(pr);

    while (sz(se) > 0)
    {
        int i = 0;

        vector <int> m; m.clear();

        while (i + 1 < sz(pr) && sz(se) > 0)
        {
            m.PB(pr[i++]);

            m.PB(*se.begin()); se.erase(se.begin());
        }

        m.PB(pr[i++]);

        ans += sz(m) / 2 - ask(m) / 2;
    }

    return ans;
}

void fnd(set <int> &se)
{
    if (sz(se) == 2)
    {
       vector <int> m; m.clear(); m.PB(0); m.PB(*se.begin());

       if (ask(m) == 0)
       {
            tr.PB(*se.begin());

            se.erase(se.begin());
       }
       else
       {
            tr.PB(*se.rbegin());

            se.erase(*se.rbegin());
       }

       return;
    }

    if (sz(se) == 3)
    {
        vector <int> m; m.clear(); m.PB(*se.begin()); se.erase(se.begin()); m.PB(*se.begin()); se.erase(se.begin());

        if (ask(m) == 0)
        {
            vector <int> pl; pl.clear();

            pl.PB(0); pl.PB(*se.begin());

            if (ask(pl) == 0) {tr.PB(*se.begin()); se.erase(*se.begin()); se.insert(m[0]); se.insert(m[1]); return;}
              else {tr.PB(m[0]); tr.PB(m[1]); return;}
        }

        set <int> st; st.clear();

        st.insert(m[0]); st.insert(m[1]);

        fnd(st);

        for (auto it : st) se.insert(it);

        return;
    }

    set <int> st; st.clear();

    int nm = sz(se) / 2;

    while (sz(st) < nm) {st.insert(*se.begin()); se.erase(se.begin());}

    if (ask(st) != 0) fnd(st);
      else if (ask(se) != 0) fnd(se);
        else
        {
            int l = *st.rbegin(), r = *se.begin();

            vector <int> m = {l, 0};

            if (ask(m) == 0) st.erase(l);
              else se.erase(r);
        }

    for (auto it : st) se.insert(it);
}

int count_mushrooms(int n)
{
    nr = n;

    tr.PB(0);

    int i = 1;

    vector <int> m; m.clear();

    m.PB(0);

    set <int> se; se.clear();

    for (int i = 1; i < n; i++) se.insert(i);

    while (i < n && sz(tr) < NEED && bad == -1)
    {
        m.PB(i);

        int val = ask(m);

        m.pop_back();

        if (val == 1) {bad = i++; break;}

        se.erase(i);

        tr.PB(i++);
    }

    while (sz(tr) < NEED && sz(se) > 0)
    {
        if (sz(se) == 1)
        {
            vector <int> m = {0, *se.begin()};

            if (ask(m) == 0) tr.PB(*se.begin());

            return sz(tr);
        }

        if (ask(se) == 0) return sz(tr);

        fnd(se);
    }

    return es_minus_3(tr, se);
}

//int main()
//{
//    iostream::sync_with_stdio(0); ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
//
//    //freopen("fcolor.in", "r", stdin); freopen("fcolor.out", "w", stdout);
//
//
//}

• Subtask 1: 0 / 100