Merge Sort
Consider a classroom with two groups of children lined up in order of height.
We want them to form one line, also arranged by height.
What's Happening Here?
What's Happening Here?
What's Happening Here?
What's Happening Here?
What's Happening Here?
What's Happening Here?
What's Happening Here?
What's Happening Here?
What's Happening Here?
What's Happening Here?
Merge Sort
Start with a pile of data to be sorted
Repeatedly divide the pile in half until you get to singletons
Repeatedly merge the results.
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split
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merge
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merge #1, 4 operations
merge #2, 4 operations
N= 4
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merge
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STOP+THINK: How many split steps?
# merges depends on log2 N
O(N log2 N)
number of objects/cases/datapoints
time
"constant" time
"linear" time
"exponential" time
"quadratic" time
