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 12.16.1) (judge verdict: Accepted)

function main(input) {
  input = input.split("\n");
  const N = input[1].split(" ");
  let problems = [];
  let problemCount = 0

  for(problemCount = 0; problemCount < N.length; problemCount++){
    problems[problemCount] = parseInt(N[problemCount], 10);
  }
  
  function compareFunc(a, b) {
    return a - b;
  }
  
  problems.sort(compareFunc);
  const ans = problems[N.length/2] - problems[N.length/2 - 1];
  
  console.log(ans);
}

main(require('fs').readFileSync('/dev/stdin', 'utf8'));