1845D - Rating System - CodeForces Solution

#include<bits/stdc++.h>
using namespace std;

#define int long long



void Parallelism_solve()
{
    int n;
    cin >> n;
    vector<int> a(n + 1, 0), b;
    for (int i = 1; i <= n; i++)
    {
        cin >> a[i];
    }
    vector<int> pre(n + 1, 0);
    for (int i = 1; i <= n; i++)
    {
        pre[i] = pre[i - 1] + a[i];
    }
    vector<int> Max(n + 5, -1e18 - 10);
    for (int i = n; i >= 1; i--)
    {
        Max[i] = max(Max[i + 1], pre[n] - pre[i]);
    }
    int ans = Max[1], p = 0;
    for (int i = 1; i <= n;i ++)
    {
        if (pre[i] + Max[i] > ans)
        {
            ans = pre[i] + Max[i];
            p = pre[i];
        }
    }
    cout << p << '\n';
}
main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int t;
    cin >> t;
    for (int i = 1; i <= t; i++)
    {
        Parallelism_solve();
    }
}