Submission #544689

#	Time	Username	Problem	Language	Result	Execution time	Memory
544689		AbdelmagedNour	Lightning Rod (NOI18_lightningrod)	C++17	80 / 100	2009 ms	262144 KiB

Main

#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
const int N=10000005;
int n,a[N],b[N],nxta[N],nxtb[N];
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin>>n;
    for(int i=0;i<n;i++){
        int x,y;
        cin>>x>>y;
        a[i]=y-x;
        b[i]=y+x;
    }
    vector<int>st;
    for(int i=n-1;i>=0;i--){
        while(!st.empty()&&a[st.back()]<a[i])st.pop_back();
        nxta[i]=(st.empty()?-1:st.back());
        st.push_back(i);
    }
    st.clear();
    for(int i=n-1;i>=0;i--){
        while(!st.empty()&&b[st.back()]<b[i])st.pop_back();
        nxtb[i]=(st.empty()?n:st.back());
        st.push_back(i);
    }
    int res=0,pos=0,mx=INT_MIN;
    while(pos<n){
        if(b[pos]<=mx){
            pos++;
            continue;
        }
        res++;
        while(nxta[pos]!=-1)pos=nxta[pos];
        mx=max(mx,b[pos]);
        pos=nxtb[pos];
    }
    cout<<res;
    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: 0 / 20