Submission #547193

#	Time	Username	Problem	Language	Result	Execution time	Memory
547193		Ahmed57	Lightning Rod (NOI18_lightningrod)	C++14	100 / 100	1720 ms	262144 KiB

Main

#include<bits/stdc++.h>
using namespace std;
const int N = 1e7+9;
int per[N] , suf[N];
int aa[N], bb[N];
int main() {
    ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    int n;cin>>n;
    for(int i = 0;i<n;i++){
        cin>>aa[i]>>bb[i];
        if(i==0){
            per[0] = aa[0]+bb[0];
        }else{
            per[i] = max(per[i-1],aa[i]+bb[i]);
        }
    }
    suf[n-1] = bb[n-1]-aa[n-1];
    for(int i = n-2;i>=0;i--){
        suf[i] = max(suf[i+1],bb[i]-aa[i]);
    }
    int ans = 0;
    for(int i = 0;i<n;i++){
        if(i==0){
            if(suf[i+1]<bb[i]-aa[i]){
                ans++;
            }
        }else if(i==n-1){
            if(per[i-1]<aa[i]+bb[i])ans++;
        }else{
            if(suf[i+1]<bb[i]-aa[i]&&per[i-1]<aa[i]+bb[i])ans++;
        }
    }
    cout<<ans<<"\n";
	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