Although it's a leetcode hard question, if you have learned the basic pseudocode of MergeSort, then it is very easy for you.

• Problem Statement: Given two sorted arrays nums1 and nums2 of size m and n respectively, return the median of the two sorted arrays.

  The overall run time complexity should be O(log (m+n)).

• Example 1:

    Input: nums1 = [1,3], nums2 = [2]
    Output: 2.00000
    Explanation: merged array = [1,2,3] and median is 2.
  

• Example 2:

    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.
  

Approach:

1. merge both the sorted arrays and make sure the merged array is also sorted(easily done by merge sort code)

2. if the length of the merged array is odd -> median = (merged[len / 2] + merged[len / 2 + 1]) / 2;

3. if the length of the merged array is even -> simply return the middle element. median = merged[len / 2];

Code:

class Solution {
    public double findMedianSortedArrays(int[] nums1, int[] nums2) {
        int mix[] = merge(nums1, nums2);
        int len = mix.length;
        double median = 0.0;
        if(len % 2 == 0){   //even 
            median = (double)(mix[(len - 1) / 2] + mix[((len - 1) / 2) + 1]) / 2;
        }
        else{
            median = mix[(len- 1) / 2];
        }
        return median;
    }

    int[] merge(int[] one, int[] two){
        int[] mix = new int[one.length + two.length];
        int i = 0; int j = 0;
        int k = 0; 
        while(i < one.length && j < two.length){
            if(one[i] < two[j]){
                mix[k] = one[i]; 
                i++; 
                // k++;
            }
            else{
                mix[k] = two[j];
                j++;
            }
            k++;
        }
        while(i < one.length){
            mix[k] = one[i];
            i++;
            k++;
        }
        while(j < two.length){
            mix[k] = two[j];
            j++;
            k++;
        }
        return mix;
    }
}

Link to The Question:

Median of Two Sorted Arrays