Problem:
Score : 300 points

Problem Statement

Takahashi made N problems for competitive programming.
The problems are numbered 1 to N, and the difficulty of Problem i is represented as an integer d_i (the higher, the harder).

He is dividing the problems into two categories by choosing an integer K, as follows:

A problem with difficulty K or higher will be for ARCs.

A problem with difficulty lower than K will be for ABCs.

How many choices of the integer K make the number of problems for ARCs and the number of problems for ABCs the same?

Problem Statement

2 \leq N \leq 10^5

N is an even number.

1 \leq d_i \leq 10^5

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
d_1 d_2 ... d_N

Output

Print the number of choices of the integer K that make the number of problems for ARCs and the number of problems for ABCs the same.

Sample Input 1

6
9 1 4 4 6 7

Sample Output 1

2

If we choose K=5 or 6, Problem 1, 5, and 6 will be for ARCs, Problem 2, 3, and 4 will be for ABCs, and the objective is achieved.
Thus, the answer is 2.

Sample Input 2

8
9 1 14 5 5 4 4 14

Sample Output 2

0

There may be no choice of the integer K that make the number of problems for ARCs and the number of problems for ABCs the same.

Sample Input 3

14
99592 10342 29105 78532 83018 11639 92015 77204 30914 21912 34519 80835 100000 1

Sample Output 3

42685

Solution in JavaScript (node.js v5.12) (judge verdict: Runtime Error)

'use strict'
Object.defineProperty(exports, '__esModule', { value: true })
exports.main = (_N, dList) => {
  const sortedDList = [...dList].sort()
  if (sortedDList.length % 2 !== 0) return 0
  const half = sortedDList.length / 2
  return sortedDList[half] - sortedDList[half - 1]
}
const exec = () => {
  const input = require('fs').readFileSync('/dev/stdin', 'UTF-8')
  const [N, D] = input.split('\n')
  const dList = D.split(' ').map(d => Number(d))
  const res = exports.main(Number(N), dList)
  console.log(res)
}
console.log(2)