Median of Two Sorted Arrays

Problem : Given two sorted arrays nums1 and nums2 of size m and n respectively, return the median of the two sorted arrays.

 ```
Input: nums1 = [1,2], nums2 = [3,4]
Output: 2.50000
Explanation: merged array = [1,2,3,4] and median is (2 + 3) / 2 = 2.5.
```