Submission #303582

#	Time	Username	Problem	Language	Result	Execution time	Memory
303582		jtnydv25	Counting Mushrooms (IOI20_mushrooms)	C++17	25 / 100	855 ms	632 KiB

mushrooms

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

#define ll long long
#define pii pair<int, int>
#define F first
#define S second
#define all(c) ((c).begin()), ((c).end())
#define sz(x) ((int)(x).size())
#define ld long double

template<class T,class U>
ostream& operator<<(ostream& os,const pair<T,U>& p){
	os<<"("<<p.first<<", "<<p.second<<")";
	return os;
}

template<class T>
ostream& operator <<(ostream& os,const vector<T>& v){
	os<<"{";
	for(int i = 0;i < (int)v.size(); i++){
		if(i)os<<", ";
		os<<v[i];
	}
	os<<"}";
	return os;
}

#ifdef LOCAL
#define cerr cout
#else
#endif

#define TRACE

#ifdef TRACE
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1>
void __f(const char* name, Arg1&& arg1){
	cerr << name << " : " << arg1 << std::endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args){
	const char* comma = strchr(names + 1, ',');cerr.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...);
}
#else
#define trace(...)
#endif



const int M = 8;

int val[200005];
struct node{
	vector<int> states;
	node* res[M];
	vector<int> ask;
	int maxQueries;
	node(){
		for(int i = 0; i < M; i++) res[i] = NULL;
		maxQueries = 0;
	}
	void compute(){
		int n = states.size();
		if(n == 1) return;
		maxQueries = 1;
		int mn = 1 << 20;
		for(int mask = 1; mask < (1 << M); mask++){
			vector<int> perm;
            for(int j = 0; j < M; j++) if(mask >> j & 1) perm.push_back(j);
            if(((int)perm.size()) == 1) continue;
            do{
                vector<int> num(M);
                for(int s : states){
                    int r = 0;
                    for(int j = 0; j + 1 < (int)perm.size(); j++) r += (s >> perm[j] & 1) != (s >> perm[j + 1] & 1);
                    num[r]++;
                }
                int V = *max_element(num.begin(), num.end());
                if(V < mn){
                    mn = V;
                    ask = perm;
                }
            }while(next_permutation(perm.begin(), perm.end()));
		}
        vector<int> perm = ask;

		vector<vector<int>> childStates(M);
		
        for(int s : states){
            int r = 0;
            for(int j = 0; j + 1 < (int)perm.size(); j++) r += (s >> perm[j] & 1) != (s >> perm[j + 1] & 1);
            childStates[r].push_back(s);
        }
		for(int i = 0; i < M; i++){
			if(!childStates[i].empty()){
				res[i] = new node();
				res[i]->states = childStates[i];
				res[i]->compute();
				maxQueries = max(maxQueries, res[i]->maxQueries + 1);
			}
		}
	}
    void get(vector<int> positions){
        if((int)states.size() == 1){
            for(int i = 0; i < M; i++) val[positions[i]] = states[0] >> i & 1;
            return;
        }

        vector<int> x;
        for(int i : ask) x.push_back(positions[i]);
        res[use_machine(x)]->get(positions);
    }
};

int get(int pos){
    return val[pos] = use_machine({0, pos});
}

struct decision_tree{
	node * root;
	decision_tree(){
		root = new node();
		for(int i = 0; i < (1 << M); i+=2) root->states.push_back(i);
		root->compute();
	}
    void get(vector<int> positions){
        root->get(positions);
    }
};

const int K = 6;

int count_mushrooms(int N) {
	decision_tree DT;
    int n = min(N, K);
    // int n = N;
    // for(int j = 1; j < N; j++) get(j);
    for(int i = 1; i < n; i += M - 1){
        int st = i, en = i + M - 2;
        if(en < n){
            vector<int> positions = {0};
            for(int j = st; j <= en; j++) positions.push_back(j);
            DT.get(positions);
        } else{
            for(int j = st; j < n; j++) get(j);
        }
    }

    int curr = n - accumulate(val, val + n, 0);
    if(n == N) return curr;
	vector<vector<int>> where(2);
    for(int i = 0; i < n; i++) where[val[i]].push_back(i);
    int id = (int)where[1].size() > (int) where[0].size();
    int R = where[id].size() - 1;
    for(int i = n; i < N; i += R){
        int st = i, en = min(N - 1, i + R - 1);
        vector<int> positions = {where[id][0]};
        for(int j = 0; j <= en - st; j++){
            positions.push_back(st + j);
            positions.push_back(where[id][j + 1]);
        }
        int V = use_machine(positions);
        assert(V % 2 == 0);
        V /= 2;
        if(id == 1) curr += V;
        else curr += en - st + 1 - V;
    }
    return curr;
}

• Subtask 1: 25 / 100