Submission #1066210

#	Time	Username	Problem	Language	Result	Execution time	Memory
1066210		Ahmed57	Counting Mushrooms (IOI20_mushrooms)	C++17	80.43 / 100	7 ms	600 KiB

mushrooms

#include "bits/stdc++.h"
using namespace std;
#include "mushrooms.h"
 mt19937 rnd;
int count_mushrooms(int n){
    rnd.seed(time(0));
    int mi = 1e9 ;
    int B = 3;
    for(int b = 3;b<=n;b++){
        int cost = b/2+2;
        int ma = (b+1)/2;
        cost+=(n-b+ma-1)/ma;
        if(cost<mi){
            mi = cost;
            B = b;
        }
    }
    vector<int> BS[2];
    int cnt = 0;
    vector<int> label;
    for(int i = 0;i<n;i++)label.push_back(i);
    shuffle(label.begin()+1,label.end(),rnd);
    vector<int> pending;
    BS[0].push_back(0);
    for(int i = 1;i<min(n,3);i++){
        if(use_machine({0,label[i]})){
            BS[1].push_back(label[i]);
        }else {
            BS[0].push_back(label[i]);
        }
    }
    int la = 2;
    for(int i = 3;i+1<min(n,B);i+=2){
        la = i+1;
        if(BS[0].size()>1){
            //A
            int an = use_machine({BS[0][0],label[i],BS[0][1],label[i+1]});
            if(an==0){
                BS[0].push_back(label[i]);
                BS[0].push_back(label[i+1]);
                continue;
            }if(an==1){
                BS[0].push_back(label[i]);
                BS[1].push_back(label[i+1]);
                continue;
            }if(an==2){
                BS[1].push_back(label[i]);
                BS[0].push_back(label[i+1]);
                continue;
            }else{
                BS[1].push_back(label[i]);
                BS[1].push_back(label[i+1]);
                continue;
            }
        }else{
            int an = use_machine({BS[1][0],label[i],BS[1][1],label[i+1]});
            if(an==0){
                BS[1].push_back(label[i]);
                BS[1].push_back(label[i+1]);
                continue;
            }if(an==1){
                BS[1].push_back(label[i]);
                BS[0].push_back(label[i+1]);
                continue;
            }if(an==2){
                BS[0].push_back(label[i]);
                BS[1].push_back(label[i+1]);
                continue;
            }else{
                BS[0].push_back(label[i]);
                BS[0].push_back(label[i+1]);
                continue;
            }
        }
    }
    if(la+1<min(n,B)){
        if(use_machine({0,label[la+1]})){
            BS[1].push_back(label[la+1]);
        }else BS[0].push_back(label[la+1]);
    }
    cnt = BS[0].size();
    int sz = max(BS[0].size(),BS[1].size());
    vector<int> bs;
    bool As = 0;
    if(BS[0].size()>BS[1].size()){
        As = 1;
        bs = BS[0];
    }else bs = BS[1];
    for(int i = B;i<n;i+=sz){
        int xd = i;
        vector<int> lol;
        int nah = 0;
        int last = -1;
        for(int j = i;j<min(n,i+sz);j++){
            nah++;
            lol.push_back(bs[j-i]);
            lol.push_back(label[j]);
            last = label[j];
        }
        int ans = use_machine(lol);
        if(ans%2){
            if(As==0){
                cnt++;
                BS[0].push_back(last);
            }else BS[1].push_back(last);
            ans--;
        }else{
            if(As==1){
                cnt++;
                BS[0].push_back(last);
            }else BS[1].push_back(last);
        }
        ans/=2;
        nah--;
        if(As==0)cnt+=ans;
        else cnt+=nah-ans;
    }
    return cnt;
}

Compilation message (stderr)

mushrooms.cpp: In function 'int count_mushrooms(int)':
mushrooms.cpp:90:13: warning: unused variable 'xd' [-Wunused-variable]
   90 |         int xd = i;
      |             ^~

• Subtask 1: 80.427 / 100