Submission #1357547

#	Time	Username	Problem	Language	Result	Execution time	Memory
1357547		baosonnguyenthe20	Lightning Rod (NOI18_lightningrod)	C++20	40 / 100	72 ms	15996 KiB

Main

#include <bits/stdc++.h>
#define fi first
#define se second
#define ll long long
#define N int(1e6)
using namespace std;
ll n, ans;
pair<ll, ll>vt[N+10];
bool ok[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>>vt[i].fi>>vt[i].se;
    vt[0].fi=vt[0].se=0;
    if(n<=2000)
    {
        sort(vt+1, vt+n+1);
        for(int i=1; i<=n; i++)
        {
            if(!ok[i])
            {
                for(int j=0; j<=n; j++)
                {
                    if(i==j) continue;
                    if(abs(vt[i].fi-vt[j].fi)<=(vt[i].se-vt[j].se)) ok[j]=1;
                }

            }

        }
        for(int i=1; i<=n; i++) if(!ok[i]) ans++;
        cout<<ans;
    }
    else
    {
        ll min1=0;
        ll max1=0;
        for(int i=1;i<=n;i++)
        {
            if(max1>=(vt[i].fi-vt[i].se)) ok[i]=1;
            max1=max(max1,vt[i].fi-vt[i].se);
        }
        for(int i=n;i>=1;i--)
        {
            if(min1<=(vt[i].se-vt[i].fi)) ok[i]=1;
            min1=min(min1,vt[i].fi+vt[i].se);
        }
        for(int i=1; i<=n; i++) if(!ok[i]) ans++;
        cout<<ans;
    }


    return 0;
}

• Subtask 1: 0 / 4
• Subtask 2: 7 / 7
• Subtask 3: 12 / 12
• Subtask 4: 21 / 21
• Subtask 5: 0 / 26
• Subtask 6: 0 / 10
• Subtask 7: 0 / 20