merge sort
DESCRIPTION
TRANSCRIPT
G R Lockwood, 2006G R Lockwood, 2006 11
Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Sort the sequence 6, 5, 8, 3, 2, 7, 1 Sort the sequence 6, 5, 8, 3, 2, 7, 1 using merge sortusing merge sort
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Split the sequence Split the sequence at at mm==((ii++jj)/2)/2
ii=1, =1, jj=7, =7, mm=4=4
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Make a recursive Make a recursive call to merge sortcall to merge sort
mm := := ((ii++jj)/2)/2= = 2.52.5=2=2
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Now sorting this Now sorting this partpart
ii=1, =1, jj=2, =2, mm=1 and =1 and make a recursive make a recursive callcall
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Sequence of length Sequence of length 1 is already sorted, 1 is already sorted, so returnso return
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Sequence of length Sequence of length 1 is sorted1 is sorted
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Return control and Return control and merge these 2 sub-merge these 2 sub-sequences into sequences into correct ordercorrect order
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Now sort the Now sort the second part of this second part of this subsequencesubsequence
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Sequence of length Sequence of length 1 is sorted1 is sorted
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Sequence of length Sequence of length 1 is sorted1 is sorted
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Merge these two Merge these two into correct orderinto correct order
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Return control to Return control to previous call.previous call.
Now merge these Now merge these two sub-sequences two sub-sequences into correct orderinto correct order
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
The recursive call The recursive call at line 7 is now at line 7 is now completedcompleted
First part of First part of sequence is now sequence is now fully sortedfully sorted
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Control now Control now returns to the very returns to the very first call of merge first call of merge sortsort
A recursive call is A recursive call is now made on the now made on the second part of the second part of the sequencesequence
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
ii=5, =5, jj=7, =7, mm=6=6 Split sequence at Split sequence at
item 6item 6
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Make a recursive Make a recursive call to sort these call to sort these two itemstwo items
Split sequence at Split sequence at item 5item 5
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Make another Make another recursive call on recursive call on the first part of this the first part of this subsequencesubsequence
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Sequence of length Sequence of length 1 is sorted1 is sorted
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Make a recursive Make a recursive call on second part call on second part of sequenceof sequence
Sequence of length Sequence of length 1 is sorted1 is sorted
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Now merge these 2 Now merge these 2 sub-sequences sub-sequences into correct orderinto correct order
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Make a recursive Make a recursive call with the call with the remaining elementremaining element
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Sequence of length Sequence of length 1 is sorted1 is sorted
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Now merge these 2 Now merge these 2 sub-sequences into sub-sequences into correct ordercorrect order
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Return to the first Return to the first callcall
Now merge these 2 Now merge these 2 sub-sequences into sub-sequences into correct ordercorrect order
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Sorting a Sequence With Merge SortSorting a Sequence With Merge Sort
Merge sort is Merge sort is completedcompleted
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