merge sort b
DESCRIPTION
TRANSCRIPT
![Page 1: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/1.jpg)
Merge sort
![Page 2: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/2.jpg)
Let’s start with an unsorted list
![Page 3: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/3.jpg)
Divide the list into two lists
![Page 4: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/4.jpg)
Divide that list up again
![Page 5: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/5.jpg)
Divide that list up again
![Page 6: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/6.jpg)
And again...
![Page 7: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/7.jpg)
A single item list must be sorted✓
![Page 8: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/8.jpg)
go to the next list, a single item list must be sorted✓
![Page 9: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/9.jpg)
jjii
KKNow take that pair and merge
![Page 10: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/10.jpg)
jjii
KK
Look down both lists taking the smallest
![Page 11: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/11.jpg)
jjii
✓KK
When both lists run out you have a sorted list
![Page 12: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/12.jpg)
jjii Now this pair is sorted
![Page 13: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/13.jpg)
✓Do the same with the next pair
![Page 14: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/14.jpg)
✓Each is a list of one item (so sorted)
![Page 15: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/15.jpg)
jjii
KK We merge again
![Page 16: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/16.jpg)
jjii
KK
Creating a new sorted list
![Page 17: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/17.jpg)
Now we have two lists of pairs...
![Page 18: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/18.jpg)
So we merge them
![Page 19: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/19.jpg)
jjii
KK
Look down both lists taking the smallest
![Page 20: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/20.jpg)
jjii
KK
![Page 21: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/21.jpg)
jjii
KK
Look down both lists taking the smallest
![Page 22: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/22.jpg)
jjii
KK
Look down both lists taking the smallest
![Page 23: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/23.jpg)
jjii
KK
Look down both lists taking the smallest
![Page 24: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/24.jpg)
jjii KK
Look down both lists taking the smallest
![Page 25: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/25.jpg)
the list is sorted and you can begin the next quarter
![Page 26: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/26.jpg)
A single item list must be sorted✓
![Page 27: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/27.jpg)
A single item list must be sorted✓
![Page 28: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/28.jpg)
jjii KK Merge this pair
![Page 29: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/29.jpg)
jjii
KK
Pick the smaller item
![Page 30: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/30.jpg)
jjii KKWhen both lists run out you have a sorted list
![Page 31: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/31.jpg)
![Page 32: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/32.jpg)
Sort the next pair
![Page 33: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/33.jpg)
A single item list must be sorted
✓
![Page 34: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/34.jpg)
A single item list must be sorted
✓
![Page 35: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/35.jpg)
Merge the single item lists
![Page 36: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/36.jpg)
jjii KK Merge this pair
![Page 37: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/37.jpg)
jjii KK
Pick the smaller item
![Page 38: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/38.jpg)
jjii KKPick the smaller item
![Page 39: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/39.jpg)
Now we have two lists of pairs...
![Page 40: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/40.jpg)
ii
jj KKSo we merge them
![Page 41: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/41.jpg)
ii
jj KK
Pick the smaller item
![Page 42: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/42.jpg)
ii jj
KKPick the smaller item
![Page 43: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/43.jpg)
ii jj KK
Pick the smaller item
![Page 44: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/44.jpg)
ii jj
KK
Pick the smaller item
![Page 45: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/45.jpg)
the pairs lists are now merged
![Page 46: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/46.jpg)
ii jj KK
Now we merge the quarters
![Page 47: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/47.jpg)
ii
jj KK
Pick the smaller item
![Page 48: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/48.jpg)
ii jj KK
and move on
![Page 49: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/49.jpg)
ii jj KK
Pick the smaller item
![Page 50: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/50.jpg)
ii jj KK
and move on
![Page 51: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/51.jpg)
ii jj KK
Pick the smaller item
![Page 52: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/52.jpg)
ii jj KK
and move on
![Page 53: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/53.jpg)
ii jj KK
Pick the smaller item
![Page 54: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/54.jpg)
ii jj KK
and move on
![Page 55: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/55.jpg)
The first half is now sorted
![Page 56: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/56.jpg)
Quickly we do the other half
![Page 57: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/57.jpg)
Divide...
![Page 58: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/58.jpg)
and Divide...
![Page 59: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/59.jpg)
and Divide until the lists can be no smaller
![Page 60: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/60.jpg)
Merge pairs...
![Page 61: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/61.jpg)
Merge quaters
![Page 62: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/62.jpg)
Finally the second half is sorted
![Page 63: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/63.jpg)
A final merge of both halves makes the list sorted
![Page 64: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/64.jpg)
ii jj KK
Merging lists takes as long as the list (order(N))
You do this log(N) timesMaking algorithm Order (N log(N))
![Page 65: Merge sort b](https://reader038.vdocuments.us/reader038/viewer/2022102716/546fa72faf7959c70a8b4669/html5/thumbnails/65.jpg)
ii jj KK
Merging lists takes as long as the list (order(N))
You do this log(N) timesMaking algorithm Order (N log(N))
Merging lists takes as long as the list (order(N))
You do this log(N) timesMaking algorithm Order (N log(N))
Pity you need extra space to ‘merge’ into otherwise it would be pretty cool