Submission #1357549

#	Time	Username	Problem	Language	Result	Execution time	Memory
1357549		baosonnguyenthe20	Lightning Rod (NOI18_lightningrod)	C++20	100 / 100	988 ms	166132 KiB

Main

#include <bits/stdc++.h>
#define fi first
#define se second
#define ll long long
#define N int(1e7)
using namespace std;
ll n, ans;
bool ok[N+10];
ll x[N+10],y[N+10];
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin>>n;
    for(int i=1; i<=n; i++) cin>>x[i]>>y[i];
    x[0]=y[0]=0;
    if(n<=2000)
    {
        for(int i=1; i<=n; i++)
        {
            if(!ok[i])
            {
                for(int j=0; j<=n; j++)
                {
                    if(i==j) continue;
                    if(abs(x[i]-x[j])<=(y[i]-y[j])) ok[j]=1;
                }

            }

        }
        for(int i=1; i<=n; i++) if(!ok[i]) ans++;
        cout<<ans;
    }
    else
    {
        ll min1=LLONG_MAX;
        ll max1=LLONG_MIN;
        for(int i=1;i<=n;i++)
        {
            if(max1>=(x[i]+y[i])) ok[i]=1;
            max1=max(max1,x[i]+y[i]);
        }
        for(int i=n;i>=1;i--)
        {
            if(min1<=(x[i]-y[i])) ok[i]=1;
            min1=min(min1,x[i]-y[i]);
        }
        for(int i=1; i<=n; i++) if(!ok[i]) ans++;
        cout<<ans;
    }


    return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 7 / 7
• Subtask 3: 12 / 12
• Subtask 4: 21 / 21
• Subtask 5: 26 / 26
• Subtask 6: 10 / 10
• Subtask 7: 20 / 20