Submission #414200

#	Time	Username	Problem	Language	Result	Execution time	Memory
414200		79brue	Counting Mushrooms (IOI20_mushrooms)	C++14	92.62 / 100	12 ms	576 KiB

mushrooms

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

using namespace std;

typedef long long ll;
const int LIM = 79;

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 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() < LIM && vec[1].size() < LIM){
        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;
    }

    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: 92.623 / 100