P22309 [CodeChef] PAPARAZI
提高-
题目描述

Read problem statements in [Bengali], [Mandarin Chinese], [Russian], and [Vietnamese] as well.

The young but promising paparazzi Gennady wants to finally become famous. To do this, he wants to take a picture of a new super star during her walk in the mountains.

It is known that the star's path in the mountains consists of $N$ sections. For each valid $i$, the $i$-th section is a vertical half-open interval with coordinates $x = i$ and $y \in [0, h_{i})$.

For each valid $i$ and $j$, our hero can take a picture of the star located in the $i$-th section of the walk when he is in the $j$-th section only if he can see the star ― that is, $i < j$ and for each $k$ ($i < k < j$), the half-open interval that makes up the $k$-th section must not intersect the line segment $[(i, h_{i}), (j, h_{j})]$.

Gennady is a paparazzi, not a programmer, so he asks you to determine the maximum distance from which he can take a picture of the star, which is the maximum value of $j-i$ over all pairs $(i, j)$. Help him become famous!

------ Input ------
The first line of the input contains a single integer $T$ denoting the number of test cases. The description of $T$ test cases follows.
The first line of each test case contains a single integer $N$.
The second line contains $N$ space-separated integers $h_{1}, h_{2}, \ldots, h_{N}$.

------ Output ------
For each test case, print a single line containing one integer ― the maximum distance.

------ Constraints ------
$1 ≤ T ≤ 10^{4}$
$2 ≤ N ≤ 5 \cdot 10^{5}$
$1 ≤ h_{i} ≤ 10^{9}$ for each valid $i$
the sum of $N$ over all test cases does not exceed $5 \cdot 10^{5}$

------ Subtasks ------
Subtask #1 (10 points): the sum of $N$ over all test cases does not exceed $500$

Subtask #2 (10 points): the sum of $N$ over all test cases does not exceed $8,000$

Subtask #3 (80 points): original constraints

----- Sample Input 1 ------
4

2

1 2

3

1 2 3

7

3 2 5 3 2 4 3

8

1 2 4 3 5 4 2 1
----- Sample Output 1 ------
1

2

3

2
----- explanation 1 ------
Example case 3:

输入格式

见题面

输出格式

见题面

样例输入
4 2 1 2 3 1 2 3 7 3 2 5 3 2 4 3 8 1 2 4 3 5 4 2 1
样例输出
1 2 3 2