4. k-way merge. Use a heap to design an O(n log k)-time to merge k sorted lists into one sorted list, where n is the total number of elements in all the input lists. Your algorithm should use space (k) of internal memory, reading the input lists as streams, and writing the output list as a stream. 4. k-way merge. Use a heap to design an O(n log k)-time to merge k sorted lists into one sorted list, where n is the total number of elements in all the input lists. Your algorithm should use space (k) of internal memory, reading the input lists as streams, and writing the output list as a stream