Array Eversion

题意翻译

给你一个长度为 $ n $ 的数组 $ a $ 。 让我们定义外翻操作。设 $ x=a_n $，然后将数组 $ a $ 分成两部分：左和右。左侧部分包含不大于 $ x $ 的 $ a $ 元素 $ (≤ x）$ 。右边部分包含严格大于$ x（>x）$的$ a $ 元素。每个部分中元素的顺序与操作前相同，即分区是稳定的。然后将数组替换为左右部分的串联。 例如，如果数组$ a $ 是 $ [2,4,1,5,3] $ ，则外翻如下：$ [2,4,1,5,3]→[2,1,3],[4,5]→[2,1,3,4,5] $ 我们从数组 $ a $ 开始，在这个数组上执行外翻。我们可以证明，经过几次外翻后，阵列 $ a $ 停止变化。输出最小值k，这样阵列在更新后就不会改变。

题目描述

You are given an array $ a $ of length $ n $ . Let's define the eversion operation. Let $ x = a_n $ . Then array $ a $ is partitioned into two parts: left and right. The left part contains the elements of $ a $ that are not greater than $ x $ ( $ \le x $ ). The right part contains the elements of $ a $ that are strictly greater than $ x $ ( $ > x $ ). The order of elements in each part is kept the same as before the operation, i. e. the partition is stable. Then the array is replaced with the concatenation of the left and the right parts. For example, if the array $ a $ is $ [2, 4, 1, 5, 3] $ , the eversion goes like this: $ [2, 4, 1, 5, 3] \to [2, 1, 3], [4, 5] \to [2, 1, 3, 4, 5] $ . We start with the array $ a $ and perform eversions on this array. We can prove that after several eversions the array $ a $ stops changing. Output the minimum number $ k $ such that the array stops changing after $ k $ eversions.

输入输出格式

输入格式

Each test contains multiple test cases. The first line contains the number of test cases $ t $ ( $ 1 \le t \le 100 $ ). Description of the test cases follows. The first line contains a single integer $ n $ ( $ 1 \le n \le 2 \cdot 10^5 $ ). The second line contains $ n $ integers $ a_1, a_2, \dots, a_n $ ( $ 1 \le a_i \le 10^9 $ ). It is guaranteed that the sum of $ n $ over all test cases does not exceed $ 2 \cdot 10^5 $ .

输出格式

For each test case print a single integer $ k $ — the number of eversions after which the array stops changing.

输入输出样例

输入样例 #1

3
5
2 4 1 5 3
5
5 3 2 4 1
4
1 1 1 1

输出样例 #1

1
2
0

说明

Consider the fist example. - The first eversion: $ a = [1, 4, 2, 5, 3] $ , $ x = 3 $ . $ [2, 4, 1, 5, 3] \to [2, 1, 3], [4, 5] \to [2, 1, 3, 4, 5] $ . - The second and following eversions: $ a = [2, 1, 3, 4, 5] $ , $ x = 5 $ . $ [2, 1, 3, 4, 5] \to [2, 1, 3, 4, 5], [] \to [2, 1, 3, 4, 5] $ . This eversion does not change the array, so the answer is $ 1 $ . Consider the second example. - The first eversion: $ a = [5, 3, 2, 4, 1] $ , $ x = 1 $ . $ [5, 3, 2, 4, 1] \to [1], [5, 3, 2, 4] \to [1, 5, 3, 2, 4] $ . - The second eversion: $ a = [1, 5, 3, 2, 4] $ , $ x = 4 $ . $ [1, 5, 3, 2, 4] \to [1, 3, 2, 4], [5] \to [1, 3, 2, 4, 5] $ . - The third and following eversions: $ a = [1, 3, 2, 4, 5] $ , $ x = 5 $ . $ [1, 3, 2, 4, 5] \to [1, 3, 2, 4, 5], [] \to [1, 3, 2, 4, 5] $ . This eversion does not change the array, so the answer is $ 2 $ .