1007 maximum subsequence sum (25 points) "PTA class a exercise"

Try one by one , Pay attention to special situations , For example, all negative numbers

#include <cstring>
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <unordered_map>
#define dd double
#define PII pair<int,int>
#define int long long
#define ll long long
using namespace std;
const dd eps = 1e-6;
const int mod = 998244353;
const int N = 1e5+10;

int arr[N];
struct node{
	int sum,front,back;
}temp,result;
signed main()
{
	int n;cin>>n;
	for(int i=0;i<n;i++)
	{
		cin>>arr[i];temp.sum += arr[i];
		if(i==0) result = temp;
		if(arr[i]>temp.sum)
		{
			temp.front = i;
			temp.sum = arr[i];
		}
		if(result.sum<temp.sum)
		{
			temp.back = i;
			result = temp;
		}
	}
	if(result.sum<0) cout<<0<<" "<<arr[0]<<" "<<arr[n-1]<<endl;
	else cout<<result.sum<<" "<<arr[result.front]<<" "<<arr[result.back]<<endl;
	return 0;
}