C. Omkar and Waterslidetime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputOmkar is building a waterslide in his water park, and he needs your help to ensure that he does it as efficiently as possible.Omkar currently has n supports arranged in a line, the i-th of which has height a_i. Omkar wants to build his waterslide from the right to the left, so his supports must be nondecreasing in height in order to support the waterslide. In 1 operation, Omkar can do the following: take any contiguous subsegment of supports which is nondecreasing by heights and add 1 to each of their heights. Help Omkar find the minimum number of operations he needs to perform to make his supports able to support his waterslide!An array b is a subsegment of an array c if b can be obtained from c by deletion of several (possibly zero or all) elements from the beginning and several (possibly zero or all) elements from the end.An array b_1, b_2, \dots, b_n is called nondecreasing if b_i\le b_{i+1} for every i from 1 to n-1.InputEach test contains multiple test cases. The first line contains the number of test cases t (1 \leq t \leq 100). Description of the test cases follows.The first line of each test case contains an integer n (1 \leq n \leq 2 \cdot 10^5) — the number of supports Omkar has.The second line of each test case contains n integers a_{1},a_{2},...,a_{n} (0 \leq a_{i} \leq 10^9) — the heights of the supports.It is guaranteed that the sum of n over all test cases does not exceed 2 \cdot 10^5.OutputFor each test case, output a single integer — the minimum number of operations Omkar needs to perform to make his supports able to support his waterslide.ExampleInput
3
4
5 3 2 5
5
1 2 3 5 3
3
1 1 1
Output
3
2
0
NoteThe subarray with which Omkar performs the operation is bolded.In the first test case:First operation:[5, 3, \textbf{2}, 5] \to [5, 3, \textbf{3}, 5]Second operation:[5, \textbf{3}, \textbf{3}, 5] \to [5, \textbf{4}, \textbf{4}, 5]Third operation:[5, \textbf{4}, \textbf{4}, 5] \to [5, \textbf{5}, \textbf{5}, 5]In the third test case, the array is already nondecreasing, so Omkar does 0 operations.
3
4
5 3 2 5
5
1 2 3 5 3
3
1 1 1

3 2 0 
['greedy', 'implementation', '*1200']