AtCoder Beginner Contest 107
D
Median of Medians
AtCoder
⌀ 2073
原题
← C→
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Problem Statement

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We will define the median of a sequence $b$ of length $M$, as follows:

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  • 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.
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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 $10$.

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Snuke comes up with the following problem.

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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 $m$.

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Constraints

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

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Input is given from Standard Input in the following format:

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N
a_1 a_2 ... a_N

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Output

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Print the median of $m$.

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样例

Input #1
3
10 30 20
Output #1
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 $30$.
Input #2
1
10
Output #2
10
Input #3
10
5 9 5 9 8 9 3 5 4 3
Output #3
8
题目信息
题号
arc101_b
时间限制
2 s
内存限制
1024 MB

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