Hey Mattia, Say n is the total number of elements in all the streams put together. The time complexity of your solution is O(n * k). Since you see every element once and k-1 comparisons are required in the worst case to find the smallest element.
This approach is actually fine if the streams are infinite in length and you require say the first 'x' sorted elements. Another solution to this problem is do a pair wise merging as we do in merge sort. For example. If there are 8 streams, we make 4 pairs and merge the 4 pairs into 4 new streams in O(n) time. Then we pair the new merged streams to get 2 streams and then finally one sorted stream. Since there will be log k iterations in this approach with each iteration taking O(n) time. The complexity in this case is O(n log k). But the problem with this approach is that you dont get the final list immediately. So it is a problem when the lists are infinitely long and you want the first 'x' elements of the sorted list fast. Thanks, Hemanth
