10497: ABC107 —— D - Median of Medians
[Creator : ]
Description
We will define the **median** of a sequence $b$ of length $M$, as follows:
- Let $b'$ be the sequence obtained by sorting $b$ in non-decreasing order. Then, the value of the $(M / 2 + 1)$-th element of $b'$ is the median of $b$. Here, $/$ is integer division, rounding down.
For example, the median of $(10, 30, 20)$ is $20$; the median of $(10, 30, 20, 40)$ is $30$; the median of $(10, 10, 10, 20, 30)$ is $10$.
Snuke comes up with the following problem.
You are given a sequence $a$ of length $N$. For each pair $(l, r)$ ($1 \leq l \leq r \leq N$), let $m_{l, r}$ be the median of the contiguous subsequence $(a_l, a_{l + 1}, ..., a_r)$ of $a$. We will list $m_{l, r}$ for all pairs $(l, r)$ to create a new sequence $m$. Find the median of $m$.
- Let $b'$ be the sequence obtained by sorting $b$ in non-decreasing order. Then, the value of the $(M / 2 + 1)$-th element of $b'$ is the median of $b$. Here, $/$ is integer division, rounding down.
For example, the median of $(10, 30, 20)$ is $20$; the median of $(10, 30, 20, 40)$ is $30$; the median of $(10, 10, 10, 20, 30)$ is $10$.
Snuke comes up with the following problem.
You are given a sequence $a$ of length $N$. For each pair $(l, r)$ ($1 \leq l \leq r \leq N$), let $m_{l, r}$ be the median of the contiguous subsequence $(a_l, a_{l + 1}, ..., a_r)$ of $a$. We will list $m_{l, r}$ for all pairs $(l, r)$ to create a new sequence $m$. Find the median of $m$.
Input
Input is given from Standard Input in the following format:
```
$N$
$a_1$ $a_2$ $...$ $a_N$
```
```
$N$
$a_1$ $a_2$ $...$ $a_N$
```
Output
Print the median of $m$.
Constraints
- $1 \leq N \leq 10^5$
- $a_i$ is an integer.
- $1 \leq a_i \leq 10^9$
- $a_i$ is an integer.
- $1 \leq a_i \leq 10^9$
Sample 1 Input
3
10 30 20
Sample 1 Output
30
The median of each contiguous subsequence of a is as follows:
- The median of (10) is 10.
- The median of (30) is 30.
- The median of (20) is 20.
- The median of (10, 30) is 30.
- The median of (30, 20) is 30.
- The median of (10, 30, 20) is 20.
Sample 2 Input
1
10
Sample 2 Output
10
Sample 3 Input
10
5 9 5 9 8 9 3 5 4 3
Sample 3 Output
8