Make Array Non-Decreasing

You are given an integer array. In one operation, you can choose an element and increment it so that the overall array becomes non-decreasing. In other words, for each index i (1 ≤ i < n), the condition arr[i] ≤ arr[i+1] must hold after performing the operations.

Find the minimum number of operations required to transform the given array into a non-decreasing array.

The operation is defined as follows:

If arr[i] is less than arr[i-1], you increment arr[i] to match arr[i-1]. Formally, for every index i from 2 to n, if arr[i] < arr[i-1], you perform an operation to add arr[i-1] - arr[i] to the total count, and set arr[i] = arr[i-1].

The mathematical formulation for the number of operations can be expressed in \( \LaTeX \) as follows:

[ \text{operations} = \sum_{i=2}^{n} \max(0, arr[i-1] - arr[i]) ]

It is guaranteed that the answer fits in a 32-bit signed integer.

inputFormat

The first line of input contains a single integer T denoting the number of test cases.

For each test case:

• The first line contains an integer N, the number of elements in the array.
• The second line contains N space-separated integers representing the array.

outputFormat

For each test case, output a single line containing the minimum number of operations required to transform the array into a non-decreasing array.

## sample

2
5
1 3 2 5 4
4
10 20 30 40

2
0

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