solution.txt

The brute force solution obviously is quite costly, i.e. O(N^3).

Since the arrays are already sorted, thus there has to be a better algorithm.

We start with the first element of each of the arrays as the first possible triplet.
Now, we need to get to the triplet that minimizes the difference between maximum and minimum element in it.

So, one way is to increase the minimum element in the triplet. So, move to the next element of the array
whose current element is the minimum of the triplet, i.e.
we have 3 pointers each pointing to the current element of the arrays, initially to 0th index of each.

Now, we move the pointer to the right of the array having minimum element in the current triplet.
We keep recalculating the required value for the current triplet and update if better than the minimum value.

So, we keep doing so, until one of the array is exhausted, i.e. any of the 3 pointers has moved to the end of its array.

This greedy solution will work intuitely but giving a proof could be little tricky!