Sort Algorithms

BUBBLE SORT

Bubble sort process:

1. Look at the first 2 items in your unordered list.
2. If they are in the correct order, do not do anything. If not, swap the items.
3. Move on to the next pair of items (2nd and 3rd items) and repeat step 2
4. Complete one pass by repeating step 3 until you have gone through the whole list.
5. At this point, the last item will be in the correct place so it can be disregarded in the next passess.
6. Repeat this whole process until there are no more swaps in the pass

Key characteristics:

• Each pass will have one less comparision than the previous pass because the last item will be in the correct place.
• The simplest sorting algorithm

DIFFERENCES

• Bubble sorts are simple compared to merge sorts so they can be easily implemented on a computer
• Bubble sorts are more efficient to checking if a list is already in order because it only requires one pass whereas a merge sort will go though the whole merge and splitting process.
• A bubble sort uses less memory than a merge sort because all of the sorting is happening on the original list. Whereas, a merge sort makes numerous lists to sort the original list.
• Bubble sorts are quite inefficient compared to a merge sort therefore, it is pretty slow especially for larger lists.

MERGE SORT

Merge sort process:

1. The main list will be split into 2 sub-lists
2. Repeat step 1 until each sub-list only contains one item
3. Merge pairs of sub-lists until each sub-list is a pair of items.
4. Each time you merge a sub-list, sort the items in each sub-list so they are in the correct order.
5. Repeat steps 3 and 4 until all of the sublists have been merged.

Key characteristics:

• With merge sorts, smaller list are easier to sort than lager ones
• It is easier to carry out a merge sort on 2 ordered lists than unordered.