CODEWITHSUNDEEP
linked-listmergesort
Colby Hester
Colby Hester

Reputation: 17

Merge sorting with linked chains in java

I am looking for a template of sorts for merging two linked chains that have already been sorted. I'm still fairly new to Java, and this seems to be a pretty challenging task to accomplish with the limited knowledge I have. I have an understanding of how to merge sort an array, but when it comes to linked lists I seem to be drawing blanks. Any help you all could give me, be it actual code or simply advise on where to start, would be greatly appreciated.

Thank you for your time!

Upvotes: 0

Views: 153

Answers (2)

Sam Holder
Sam Holder

Reputation: 32936

Can't you look at the first element in each list and take the smallest. This is the start of the new list. Remove this from the front ofwhichever list it came from. Now look at the first element again and take the smallest and make it the second element in the new list. Then just repeat this process zipping the two lists together.

If you want to avoid creating a new list the just find the smallest then look at the thing is pointing at and the beginning of the other list and see which is smaller. If you are not already pointing at the smaller one the update the pointer so it is. Then rinse and repeat.

Upvotes: 0

Steve
Steve

Reputation: 11963

If the two linked list are already sorted, then it is so easy to merge those two together. I am gonna tell you the algorithm but you need to write the code yourself since it seems like a school project. First you make a new linked list, and then assign the head of the new list to be the min of list1Head and list2Head, then you just walk the two list, each time picking the min of the current node of the two list and append to the new created list, make the current to be .Next if it got picked. If one of the list doesn't have more nodes, then append the rest of another list directly to the new list. Done

Upvotes: 1

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