Submission #414290

#	Time	Username	Problem	Language	Result	Execution time	Memory
414290		79brue	Counting Mushrooms (IOI20_mushrooms)	C++14	100 / 100	11 ms	380 KiB

mushrooms

#include <bits/stdc++.h>
#include "mushrooms.h"

using namespace std;

typedef long long ll;
const int LIM = 115;

int countIfNIsSmall(int n){
    int ans = 1;
    for(int i=1; i<n; i+=2){
        if(i==n-1) ans += 1 - use_machine(vector<int> {i, 0});
        else ans += 2 - use_machine(vector<int> {i, 0, i+1});
    }
    return ans;
}

int n;
int arr[20002];
int pointer = 1;
vector<int> vec[2];
int ans;

int need;

int count_mushrooms(int n){
    if(n<=400) return countIfNIsSmall(n);

    arr[0] = 0;
    while(vec[0].size() < 2 && vec[1].size() < 2){
        if(use_machine(vector<int> {0, pointer}) == 1){
            arr[pointer] = 1;
            vec[1].push_back(pointer);
        }
        else{
            arr[pointer] = 0;
            vec[0].push_back(pointer);
        }
        pointer++;
    }

    while(vec[0].size() < 3 && vec[1].size() < 3){
        int mode = (vec[0].size() >= 2 ? 0 : 1);
        int tmp = use_machine(vector<int> {vec[mode][0], pointer, vec[mode][1], pointer+1});

        arr[pointer] = mode ^ (tmp >= 2);
        vec[arr[pointer]].push_back(pointer);

        arr[pointer+1] = mode ^ (tmp % 2);
        vec[arr[pointer+1]].push_back(pointer+1);

        pointer += 2;
    }

    int counter = 0;
//    while((vec[0].size() < LIM && vec[1].size() < LIM) || need){
    while(++counter <= 75 || need){
        int mode = (vec[0].size() > vec[1].size() ? 0 : 1);
        if(!need){
            int tmp = use_machine(vector<int> {pointer, vec[mode][0], pointer+1, vec[mode][1], pointer+2, vec[mode][2]});

            arr[pointer] = mode ^ (tmp % 2);
            vec[arr[pointer]].push_back(pointer);

            if(tmp/2 == 0){
                arr[pointer+1] = arr[pointer+2] = mode;
                vec[mode].push_back(pointer+1);
                vec[mode].push_back(pointer+2);
            }
            else if(tmp/2 == 2){
                arr[pointer+1] = arr[pointer+2] = !mode;
                vec[!mode].push_back(pointer+1);
                vec[!mode].push_back(pointer+2);
            }
            else{
                need = pointer+2;
            }
            pointer += 3;
        }
        else if((int)vec[!mode].size() >= 2){
            int tmp = use_machine(vector<int> {vec[!mode][0], need-1, vec[!mode][1], vec[mode][0], need,
                                               vec[mode][1], pointer, vec[mode][2], pointer+1}) - 1;

            if(tmp >= 4){
                arr[need-1] = mode, arr[need] = !mode;
                vec[mode].push_back(need-1);
                vec[!mode].push_back(need);
            }
            else{
                arr[need-1] = !mode, arr[need] = mode;
                vec[mode].push_back(need);
                vec[!mode].push_back(need-1);
            }
            need = 0;
            tmp %= 4;

            arr[pointer] = mode ^ (tmp >= 2);
            vec[arr[pointer]].push_back(pointer);

            arr[pointer+1] = mode ^ (tmp%2);
            vec[arr[pointer+1]].push_back(pointer+1);

            pointer += 2;
        }
        else{
            int tmp = use_machine(vector<int> {need, vec[mode][0], pointer, vec[mode][1], pointer+1, vec[mode][2]});

            arr[need] = mode ^ (tmp % 2);
            vec[arr[need]].push_back(need);

            arr[need-1] = !arr[need];
            vec[arr[need-1]].push_back(need-1);
            need = 0;

            if(tmp/2 == 0){
                arr[pointer] = arr[pointer+1] = mode;
                vec[mode].push_back(pointer);
                vec[mode].push_back(pointer+1);
            }
            else if(tmp/2 == 2){
                arr[pointer] = arr[pointer+1] = !mode;
                vec[!mode].push_back(pointer);
                vec[!mode].push_back(pointer+1);
            }
            else{
                need = pointer+1;
            }
            pointer += 2;
        }
    }

    while(pointer < n){
        int mode = (vec[0].size() >= vec[1].size() ? 0 : 1);
        vector<int> queryVec (1, pointer++);
        queryVec.push_back(vec[mode][0]);

        for(int i=1; i<(int)vec[mode].size() && pointer<n; i++){
            queryVec.push_back(pointer++);
            queryVec.push_back(vec[mode][i]);
        }

        int ret = use_machine(queryVec);
        int spnt = queryVec[0];

        arr[spnt] = mode ^ (ret % 2);
        vec[arr[spnt]].push_back(spnt);
        ret /= 2;

        for(int j=spnt+1; j<pointer; j++){
            if(j <= spnt+ret) arr[j] = !mode;
            else arr[j] = mode;
        }
    }

    for(int i=0; i<n; i++){
        if(arr[i] == 0) ans++;
    }
    return ans;
}

• Subtask 1: 100 / 100