题目描述
Call an array $a$ of length $n$ sorted if $a_1 \leq a_2 \leq \ldots \leq a_{n-1} \leq a_n$.
Ntarsis has an array $a$ of length $n$.
He is allowed to perform one type of operation on it (zero or more times):
- Choose an index $i$ ($1 \leq i \leq n-1$).
- Add $1$ to $a_1, a_2, \ldots, a_i$.
- Subtract $1$ from $a_{i+1}, a_{i+2}, \ldots, a_n$.
The values of $a$ can be negative after an operation.
Determine the minimum operations needed to make $a$ not sorted.
Input
Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 100$). The description of the test cases follows.
The first line of each test case contains a single integer $n$ ($2 \leq n \leq 500$) — the length of the array $a$.
The next line contains $n$ integers $a_1, a_2, \ldots, a_n$ ($1 \leq a_i \leq 10^9$) — the values of array $a$.
It is guaranteed that the sum of $n$ across all test cases does not exceed $500$.
Output
Output the minimum number of operations needed to make the array not sorted.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
样例输出
提示
In the first case, we can perform $1$ operation to make the array not sorted:
- Pick $i = 1$. The array $a$ then becomes $[2, 0]$, which is not sorted.
In the second case, we can perform $2$ operations to make the array not sorted:
- Pick $i = 3$. The array $a$ then becomes $[2, 9, 11, 12]$.
- Pick $i = 3$. The array $a$ then becomes $[3, 10, 12, 11]$, which is not sorted.
It can be proven that $1$ and $2$ operations are the minimal numbers of operations in the first and second test cases, respectively.
In the third case, the array is already not sorted, so we perform $0$ operations.