Submission #1105226

#	Time	Username	Problem	Language	Result	Execution time	Memory
1105226		alexdd	Fire (BOI24_fire)	C++17	40 / 100	2084 ms	2664 KiB

Main

#include <bits/stdc++.h>
using namespace std;
const int INF = 1e9;
int n,m;
pair<int,int> v[200005];
int nxt[200005];
int get_ult(int lim)
{
    int st=0,dr=n,ans=0;
    while(st<=dr)
    {
        int mij=(st+dr)/2;
        if(v[mij].first <= lim)
        {
            ans = mij;
            st = mij+1;
        }
        else
            dr = mij-1;
    }
    return ans;
}
void calc_nxt()
{
    for(int i=1;i<=n;i++)
    {
        int mxm=v[i].second;
        nxt[i]=-1;
        for(int j=1;j<=get_ult(v[i].second);j++)
        {
            if(v[j].second > mxm)
            {
                mxm = v[j].second;
                nxt[i] = j;
            }
        }
        if(nxt[i]==i) nxt[i] = -1;
        //cout<<i<<" "<<nxt[i]<<" nxt\n";
    }
}
int main()
{
    cin>>n>>m;
    for(int i=1;i<=n;i++)
    {
        cin>>v[i].first>>v[i].second;
        if(v[i].first > v[i].second)
            v[i].second += m;
    }
    sort(v+1,v+1+n);
    calc_nxt();
    int rez=INF;
    for(int i=1;i<=n;i++)
    {
        if(v[i].second >= m)
        {
            int unde=-1,mxm=-1;
            for(int j=1;j<=get_ult(v[i].second-m);j++)
            {
                if(v[j].second > mxm)
                {
                    mxm = v[j].second;
                    unde = j;
                }
            }
            if(unde==i) unde = -1;

            int cur=unde,cnt=1;
            while(cur!=-1)
            {
                cnt++;
                if(v[cur].second >= v[i].first)
                    break;
                cur = nxt[cur];
            }
            if(cur!=-1) rez = min(rez, cnt);
        }
    }
    if(rez==INF)
        rez=-1;
    cout<<rez;
    return 0;
}

• Subtask 1: 14 / 14
• Subtask 2: 17 / 17
• Subtask 3: 9 / 9
• Subtask 4: 0 / 13
• Subtask 5: 0 / 21
• Subtask 6: 0 / 26