Submission #484977

#	Time	Username	Problem	Language	Result	Execution time	Memory
484977		M4mou	Counting Mushrooms (IOI20_mushrooms)	C++17	91.13 / 100	9 ms	320 KiB

mushrooms

#include <bits/stdc++.h>
#include "mushrooms.h"
#pragma GCC optimize ("Ofast")
#pragma GCC target ("avx2")

using namespace std;

using ll  = long long;
using vi  = vector<int>;

#define pb push_back
#define ff first
#define ss second
#define lb lower_bound
#define all(x) (x).begin() , (x).end()



string s;/*
int use_machine(vector<int> a){
    int c = 0;
    for(int i = 1;i<a.size();i++){
        if(s[a[i]] != s[a[i-1]])c++;
    }
    return c;
}*/
int count_mushrooms(int n) {
    int cnt = 1;
    if(n < 226){
        
        for(int i = 1;i<n;i++){
        vector<int> a;
        a.push_back(0);
        a.push_back(i);
        int x = use_machine(a);
        if(x == 0)cnt++;
        }
        return cnt;
    }
    int k = 220;


    vector<int>arrA, arrB;
    arrA.pb(0);
    for(int i = 1;i<3;i++){
        vector<int> a;
        a.push_back(0);
        a.push_back(i);
        int x = use_machine(a);
        if(x == 0){
            arrA.pb(i);
            cnt++;
        }
        else arrB.pb(i);
    }


    for(int i = 3;i<k;i+=2){
        vector<int> a;
        if(arrA.size() > arrB.size()){
            a = {0,i,arrA[1],i+1};
            int x = use_machine(a);
            if(x == 0){
                arrA.pb(i);
                arrA.pb(i+1);
            }else if(x == 1){
                arrA.pb(i);
                arrB.pb(i+1);
            }else if(x == 2){
                arrB.pb(i);
                arrA.pb(i+1);
            }else {
                arrB.pb(i);
                arrB.pb(i+1);
            }
        }
        else {
            a = {arrB[0],i,arrB[1],i+1};
            int x = use_machine(a);
            if(x == 0){
                arrB.pb(i);
                arrB.pb(i+1);
            }
            else if( x== 1){
                arrB.pb(i);
                arrA.pb(i+1);
            }
            else if(x == 2){
                arrA.pb(i);
                arrB.pb(i+1);
            }
            else {
                arrA.pb(i);
                arrA.pb(i+1);
            }
        }
    }

    cnt = arrA.size();
#define sz(x) (int)x.size()
    {
        int i = k+1;
        while(i<n){
             if(sz(arrA) >= sz(arrB)){
            vector<int> a;
            for(int j : arrA){
                a.pb(j);
                a.pb(i);
                i++;
                if(i == n)break;
            }
            int x = use_machine(a);
            cnt += (int)(a.size()/2) - (x+1)/2;
            if(x%2){
                arrB.pb(a.back());
            }
            else arrA.pb(a.back());
            }
             else {
                vector<int> b;
            for(int j : arrB){
                b.pb(j);
                b.pb(i);
                i++;
                if(i == n)break;
            }
            int x = use_machine(b);
            cnt += (x+1)/2;
             if(x%2){
                arrA.pb(b.back());
            }
            else arrB.pb(b.back());
             }

        }
    }
 
    return cnt;

}/*
int main(){
    while(1){

        cin >> s;
        cout << count_mushrooms(s.size()) << endl;
    }
}*/

• Subtask 1: 91.129 / 100