以CF-1845D为例

#include <bits/stdc++.h>

using namespace std;

typedef long long LL;
typedef pair<int, int> PII;

const int N = 3e5 + 10;

LL n;
LL a[N];

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);

    int T;
    cin >> T;

    while (T -- )    
    {
        cin >> n;

        LL s = 0, maxs = 0, anss = 0, p = 0;
        for (int i = 1; i <= n; i ++ )
        {
            cin >> a[i];
            s += a[i];
            maxs = max(maxs, s);

            if (maxs - s > anss)
            {
                anss = maxs - s;
                p = maxs;
            }
        }

        cout << p << '\n';
    }
}