#include <bits/stdc++.h>   using namespace std;   template <typename T>   void read(T &x) {     x = 0;     char ch = getchar();     long long fh = 1;     while (ch <  0  || ch >  9 ) {       if (ch ==  - ) fh = -1;       ch = getchar();     }     while (ch >=  0  && ch <=  9 ) x = x * 10 + ch -  0 , ch = getchar();     x *= fh;   }   template <typename T>   void write(T x) {     if (x < 0) x = -x, putchar( - );     if (x > 9) write(x / 10);     putchar(x % 10 +  0 );   }   template <typename T>   void writeln(T x) {     write(x);     puts(  );   }   long long n, a[100005];   signed main() {     ios::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     long long t;     cin >> t;     while (t--) {       cin >> n;       for (long long i = 1; i <= n; i++) cin >> a[i];       long long x = 0;       for (long long i = n; i >= 1; i--)         if (a[i] < 0)           x += -a[i];         else if (x >= a[i])           x -= a[i];         else           x = 0;       cout << x << endl;     }     return 0;   }   