797B. Odd sum

B. Odd sum：题目

一道小小的贪心

#include <bits/stdc++.h>
using namespace std;
#define int long long
vector<int> a((int)6e5);
vector<int> b((int)6e5), c[(int)6e5];
const int mod = 1e9 + 7;
string s;
multiset<int> se;
signed main()
{
    int n;
    cin >> n;
	int res = -0x3f3f3f3f;
    for (int i = 0; i < n; i++)
    {
		cin>>a[i];
		if (a[i]&1) res = max(res,a[i]);
	}
	sort(a.begin(),a.begin()+n);
	int sum = 0,cou = 0x3f3f3f3f;
	for (int i=n-1;i>=0;i--)
	{
		if (a[i]>0) sum+=a[i];
		if (a[i]&1)
		{
			if (abs(a[i])<abs(cou)) cou = abs(a[i]);
		}
	}
	if (sum&1) res = sum;
	else res = max(res,sum-cou);
	cout<<res<<endl;
}