My approach to solving HackerRank’s Find the Median code challenge.

Problem

The median of a list of numbers is essentially its middle element after sorting. The same number of elements occur after it as before. Given a list of numbers with an odd number of elements, find the median?

Example

arr = [5, 3, 1, 2, 4]

The sorted array arr = [1, 2, 3, 4, 5]. The middle element and the median is 3.

Input format

The first line contains the integer n, the size of arr.

The second line contains n space-separated integers arr[i].

Returns

int: the median of the array.

Sample input

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17
20 1 2 4 6 5 3

Sample output

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13

Solution

We start by sorting our given array in ascending order and saving the results as a sorted array (strArr) variable.

After that, we find the array's middle point by dividing the array's length by 2 and using Math.floor() to round up the number.

Then we check to see if the array's length is even or odd and return the results based on the evaluation.

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1function findMedian(arr) {
2  const srtArr = arr.sort((a, b) => a - b);
3  const mid = Math.floor(srtArr.length / 2);
4
5  if (srtArr.length % 2 === 0) {
6    return (srtArr[mid - 1] + srtArr[mid]) / 2;
7  }
8
9  return srtArr[mid];
10}

Appendix

• Array.sort()
• Math.floor()
• Remainder (%)