Array Cancellation

1000ms

262144K

Description:

You're given an array $$$a$$$ of $$$n$$$ integers, such that $$$a_1 + a_2 + \cdots + a_n = 0$$$.

In one operation, you can choose two different indices $$$i$$$ and $$$j$$$ ($$$1 \le i, j \le n$$$), decrement $$$a_i$$$ by one and increment $$$a_j$$$ by one. If $$$i < j$$$ this operation is free, otherwise it costs one coin.

How many coins do you have to spend in order to make all elements equal to $$$0$$$?

Input:

Each test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 5000$$$). Description of the test cases follows.

The first line of each test case contains an integer $$$n$$$ ($$$1 \le n \le 10^5$$$) — the number of elements.

The next line contains $$$n$$$ integers $$$a_1, \ldots, a_n$$$ ($$$-10^9 \le a_i \le 10^9$$$). It is given that $$$\sum_{i=1}^n a_i = 0$$$.

It is guaranteed that the sum of $$$n$$$ over all test cases does not exceed $$$10^5$$$.

Output:

For each test case, print the minimum number of coins we have to spend in order to make all elements equal to $$$0$$$.

Sample Input:

7
4
-3 5 -3 1
2
1 -1
4
-3 2 -3 4
4
-1 1 1 -1
7
-5 7 -6 -4 17 -13 4
6
-1000000000 -1000000000 -1000000000 1000000000 1000000000 1000000000
1
0

Sample Output:

Note:

Possible strategy for the first test case:

Do $$$(i=2, j=3)$$$ three times (free), $$$a = [-3, 2, 0, 1]$$$.
Do $$$(i=2, j=1)$$$ two times (pay two coins), $$$a = [-1, 0, 0, 1]$$$.
Do $$$(i=4, j=1)$$$ one time (pay one coin), $$$a = [0, 0, 0, 0]$$$.

Informação

Provedor Codeforces

Código CF1405B