31 lines
1.7 KiB
Plaintext
31 lines
1.7 KiB
Plaintext
{{Sorting Algorithm}}
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The '''Comb Sort''' is a variant of the [[Bubble Sort]]. Like the [[Shell sort]], the Comb Sort increases the gap used in comparisons and exchanges (dividing the gap by <math>(1-e^{-\varphi})^{-1} \approx 1.247330950103979</math> works best, but 1.3 may be more practical). Some implementations use the insertion sort once the gap is less than a certain amount. See the [[wp:Comb sort|article on Wikipedia]].
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Variants:
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*Combsort11 makes sure the gap ends in (11, 8, 6, 4, 3, 2, 1), which is significantly faster than the other two possible endings
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*Combsort with different endings changes to a more efficient sort when the data is almost sorted (when the gap is small). Comb sort with a low gap isn't much better than the Bubble Sort.
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Pseudocode:
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'''function''' combsort('''array''' input)
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gap := input'''.size''' ''//initialize gap size''
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'''loop until''' gap = 1 '''and''' swaps = 0
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''//update the gap value for a next comb. Below is an example''
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gap := int(gap / 1.25)
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'''if''' gap < 1
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''//minimum gap is 1''
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gap := 1
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'''end if'''
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i := 0
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swaps := 0 ''//see [[Bubble Sort]] for an explanation''
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''//a single "comb" over the input list''
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'''loop until''' i + gap >= input'''.size''' ''//see [[Shell sort]] for similar idea''
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'''if''' input[i] > input[i+gap]
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'''swap'''(input[i], input[i+gap])
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swaps := 1 ''// Flag a swap has occurred, so the''
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''// list is not guaranteed sorted''
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'''end if'''
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i := i + 1
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'''end loop'''
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'''end loop'''
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'''end function'''
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