CF1201C · Maximum Median

• 难度：1400
• 标签：binary search、greedy、math、sortings
• 链接：https://codeforces.com/problemset/problem/1201/C
• 时间限制：2 seconds　内存限制：256 megabytes
• 出现位置：Day27-阶段模拟6-S T1T2稳分卷

英文原题面

Statement

You are given an array $a$ of $n$ integers, where $n$ is odd. You can make the following operation with it:

• Choose one of the elements of the array (for example $a_i$) and increase it by $1$ (that is, replace it with $a_i + 1$).

You want to make the median of the array the largest possible using at most $k$ operations. The median of the odd-sized array is the middle element after the array is sorted in non-decreasing order. For example, the median of the array $[1, 5, 2, 3, 5]$ is $3$.

Input

The first line contains two integers $n$ and $k$ ($1 \le n \le 2 \cdot 10^5$, $n$ is odd, $1 \le k \le 10^9$) — the number of elements in the array and the largest number of operations you can make. The second line contains $n$ integers $a_1, a_2, \ldots, a_n$ ($1 \le a_i \le 10^9$).

Output

Print a single integer — the maximum possible median after the operations.

样例

样例 1

输入：

3 2
1 3 5

输出：

5

样例 2

输入：

5 5
1 2 1 1 1

输出：

3

样例 3

输入：

7 7
4 1 2 4 3 4 4

输出：

5

样例解释（英文原文）

In the first example, you can increase the second element twice. Than array will be $[1, 5, 5]$ and it's median is $5$. In the second example, it is optimal to increase the second number and than increase third and fifth. This way the answer is $3$. In the third example, you can make four operations: increase first, fourth, sixth, seventh element. This way the array will be $[5, 1, 2, 5, 3, 5, 5]$ and the median will be $5$.