Statement : D. Me When Median Problem
You are given two arrays of positive integers $a$ and $b$, both of length $n$. You will perform the following operation exactly $n - 1$ times:
- let $m$ be the current length of $a$ and $b$, note that the lengths will always be equal.
- select an integer $i$ ($1 \le i \lt m$): let $S$ be the multiset $\{a_i, a_{i + 1}, b_i, b_{i + 1}\}$
- sort the elements of $S$ such that $s_1 \le s_2 \le s_3 \le s_4$.
- now replace $a_i, a_{i + 1}$ with $s_2$ and $b_i, b_{i + 1}$ with $s_3$. More formally, replace $a$ with $[a_1,a_2,\ldots,a_{i - 1},s_2,a_{i + 2},\ldots,a_m]$, and replace $b$ with $[b_1,b_2,\ldots,b_{i - 1},s_3,b_{i + 2},\ldots,b_m]$.
After performing all operations, there will be exactly $1$ element remaining in both $a$ and $b$. Determine the maximum value of $\min(a_1, b_1)$ attainable if you perform operations optimally.
Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 10^4$). The description of the test cases follows.
The first line of each testcase contains an integer $n$ ($1 \le n \le 10^5$) — the length of the arrays $a$ and $b$.
The second line of each testcase contains $n$ integers $a_1,a_2,\ldots,a_{n}$ ($1 \le a_i \le 2 \cdot n$).
The third line of each testcase contains $n$ integers $b_1,b_2,\ldots,b_{n}$ ($1 \le b_i \le 2 \cdot n$).
It is guaranteed that the sum of $n$ over all test cases does not exceed $10^5$.
For each testcase, output the maximum value of $\min(a_1,b_1)$ attainable.
Input
6
1
1
2
3
2 4 5
1 3 6
4
7 5 4 8
4 6 7 8
8
8 7 13 11 1 10 4 5
11 11 12 8 9 2 3 13
9
16 1 9 12 5 18 10 10 16
14 6 7 11 12 17 18 3 17
6
3 6 12 4 10 12
2 3 2 7 8 9
Output
1
3
6
8
14
8
Note
In the first example, we do not need to perform any operations, so the answer is just $\min(1, 2)$ which is $1$.
For the second example, we can do the following sequence of moves:
-
select $i = 1$ and then: $S = \{2, 4, 1, 3\}$, $s_1 = 1$, $s_2 = 2$, $s_3 = 3$, $s_4 = 4$
-
$a = [\color{red}{2, 4}, 5] \rightarrow [\color{red}{2}, 5]$
-
$b = [\color{red}{1, 3}, 6] \rightarrow [\color{red}{3}, 6]$
-
select $i = 1$ and then $S = \{2, 5, 3, 6\}$, $s_1 = 2$, $s_2 = 3$, $s_3 = 5$, $s_4 = 6$
-
$a = [\color{red}{2, 5}] \rightarrow [\color{red}{3}]$
-
$b = [\color{red}{3, 6}] \rightarrow [\color{red}{5}]$
The answer is then $\min(3, 5)$ which is $3$, it can be proven that this is optimal.