P6402 [CF1979A] Guess the Maximum
入门
题目描述

Alice and Bob came up with a rather strange game. They have an array of integers $a_1, a_2,\ldots, a_n$. Alice chooses a certain integer $k$ and tells it to Bob, then the following happens:

  • Bob chooses two integers $i$ and $j$ ($1 \le i < j \le n$), and then finds the maximum among the integers $a_i, a_{i + 1},\ldots, a_j$;
  • If the obtained maximum is strictly greater than $k$, Alice wins, otherwise Bob wins.

Help Alice find the maximum $k$ at which she is guaranteed to win.

Input

Each test consists of multiple test cases. The first line contains a single integer $t$ ($1 \le t \le 10^4$) — the number of test cases. The description of the test cases follows.

The first line of each test case contains a single integer $n$ ($2 \le n \le 5 \cdot 10^4$) — the number of elements in the array.

The second line of each test case contains $n$ integers $a_1, a_2,\ldots, a_n$ ($1 \le a_i \le 10^9$) — the elements of the array.

It is guaranteed that the sum of $n$ over all test cases does not exceed $5 \cdot 10^4$.

Output

For each test case, output one integer — the maximum integer $k$ at which Alice is guaranteed to win.

输入格式

见题面 Input 部分

输出格式

见题面 Output 部分

样例输入
6 4 2 4 1 7 5 1 2 3 4 5 2 1 1 3 37 8 16 5 10 10 10 10 9 10 3 12 9 5 2 3 2 9 8 2
样例输出
3 1 0 15 9 2
提示

In the first test case, all possible subsegments that Bob can choose look as follows: $[2, 4], [2, 4, 1], [2, 4, 1, 7], [4, 1], [4, 1, 7], [1, 7]$. The maximums on the subsegments are respectively equal to $4, 4, 7, 4, 7, 7$. It can be shown that $3$ is the largest integer such that any of the maximums will be strictly greater than it.

In the third test case, the only segment that Bob can choose is $[1, 1]$. So the answer is $0$.