Problem10497--ABC107 —— D - Median of Medians

10497: ABC107 —— D - Median of Medians

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Time Limit : 1.000 sec  Memory Limit : 512 MiB

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 $m$.

Input

Input is given from Standard Input in the following format:

```
$N$
$a_1$ $a_2$ $...$ $a_N$
```

Output

Print the median of $m$.

Constraints

-   $1 \leq N \leq 10^5$
-   $a_i$ is an integer.
-   $1 \leq a_i \leq 10^9$

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.
Thus, m = (10, 30, 20, 30, 30, 20) and the median of m is 30.

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

Source/Category