Trapping Rain Water

You are provided with an array ARR of integers representing an elevation map, where ARR[i] denotes the elevation of the ith bar. Determine the maximum amount of rainwater that can be trapped between these bars.

Input:

The first line contains an integer 'T', the number of test cases.
For each test case:
The first line contains an integer 'N', the size of the array/list.
The second line consists of 'N' space-separated integers representing the heights of the bars.

Output:

For each test case, output a single integer representing the total volume of trapped rainwater.

Example:

Input:
2
4
0 1 0 2
6
0 1 3 0 1 2

Output:
1
5

Constraints:

• 1 <= T <= 10
• 0 <= N <= 104
• 0 <= ARR[i] <= 109
• Time Limit: 1 sec

Note:

The width of each bar is 1. You are not required to print anything; the printing is already taken care of by the provided function definition.