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: Wrong Answer)

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