https://codeforces.com/contest/1845/problem/D

 #include<bits/stdc++.h>
using namespace std;
#define endl '\n'
#define int long long 
//typedef __int128 LL;//2的128
typedef long long ll; //2的64
// 1e9,, 1e19,,1e38
int n,ans,st;
int a[300010];
int maxd;
int minx;
int inf=1e18;
void solve()
{cin>>n;
maxd=-inf; minx=inf;
ans=0;
     for(int i=1;i<=n;i++)  
        cin>>st,a[i]=a[i-1]+st;
        for(int i=n;i>=0;i--)
{
    if(maxd<a[i]-minx)
    {
        maxd=a[i]-minx; ans=a[i];
    }
 minx=min(minx,a[i]);

}
        cout<<ans<<endl;
}

signed main()
{
    ios::sync_with_stdio(false);
cin.tie(0),cout.tie(0);
    int t; cin>>t;
    while(t--)
{
    solve();
}


    return 0;
}