Submission #391248

#	Time	Username	Problem	Language	Result	Execution time	Memory
391248		IloveN	Counting Mushrooms (IOI20_mushrooms)	C++14	25 / 100	156 ms	584 KiB

mushrooms

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

using namespace std;
#define ll long long
#define pii pair<int,int>
#define pll pair<ll,ll>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define all(vr) vr.begin(),vr.end()
#define vi vector<int>
#define vll vector<ll>
const int N=1e5+10,K=142;

int count_mushrooms(int n)
{
    if (n<=400)
    {
        int cnt=1;
        for (int i=1;i<n;i+=2)
        {
            vi vt;
            vt.eb(i);
            vt.eb(0);
            if (i+1<n) vt.eb(i+1);
            cnt+=vt.size()-1-use_machine(vt);
        }
        return cnt;
    }
    vi S[2];
    S[0].eb(0);
    int len=1;
    int i=1;
    while (len<2)
    {
        vi vt={0,i};
        S[use_machine(vt)].eb(i++);
        len=max(S[0].size(),S[1].size());
    }
    int inv=0,v1,v2;
    if (S[0].size()==2)
    {
        v1=S[0][0];
        v2=S[0][1];
    }
    else
    {
        v1=S[1][0];
        v2=S[1][1];
        inv=1;
    }
    while (i<n)
    {
        vi vt;
        vt.eb(i);
        vt.eb(v1);
        if (i+1<n) vt.eb(i+1),vt.eb(v2);
        int tmp=use_machine(vt);
        S[(tmp&1)^inv].eb(i++);
        if (vt.size()==4)
            S[((tmp>>1)&1)^inv].eb(i++);
        len=max(S[0].size(),S[1].size());
    }
    if ((int)S[0].size()==len) inv=0;
    else inv=1;
    int res=S[0].size();
    while (i<n)
    {
        vi vt={S[inv][0]};
        for (int j=1;j<len && i<n;j++)
        {
            vt.eb(i++);
            vt.eb(S[inv][j]);
        }
        int tmp=use_machine(vt);
        if (inv) res+=vt.size()/2-tmp/2;
        else res+=tmp/2;
    }
    return res;
}

• Subtask 1: 25 / 100