Commit 9cd30ee

author

Amogh Singhal

authored

Create quick_sort.py

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	`1`	`+def swap(a, b):`
	`2`	`+ temp = a`
	`3`	`+ a = b`
	`4`	`+ b = temp`
	`5`	`+`
	`6`	`+def quick_sort(array):`
	`7`	`+ quick_sort_helper(array, 0, len(array)-1)`
	`8`	`+`
	`9`	`+def quick_sort_helper(arr, first, last):`
	`10`	`+ if first < last:`
	`11`	`+ split_point = partition(arr, first, last)`
	`12`	`+`
	`13`	`+ quick_sort_helper(arr, first, split_point - 1)`
	`14`	`+ quick_sort_helper(arr, split_point + 1, last)`
	`15`	`+`
	`16`	`+def partition(arr, first, last):`
	`17`	`+ pivot = arr[first]`
	`18`	`+`
	`19`	`+ left = first + 1`
	`20`	`+ right = last`
	`21`	`+`
	`22`	`+ done = False`
	`23`	`+`
	`24`	`+ while not done:`
	`25`	`+`
	`26`	`+ # move left and right pointers to locate split_point`
	`27`	`+ while left <= right and arr[left] <= pivot:`
	`28`	`+ left += 1`
	`29`	`+ while arr[right] >= pivot and right >= left:`
	`30`	`+ right -= 1`
	`31`	`+`
	`32`	`+ # when both pointers cross each other`
	`33`	`+ # we have located the split_point`
	`34`	`+ if right < left:`
	`35`	`+ done = True`
	`36`	`+ else:`
	`37`	`+ # swap the left and right elements`
	`38`	`+ swap(arr[left], arr[right])`
	`39`	`+`
	`40`	`+ # swap the first and right elements`
	`41`	`+ swap(arr[first], arr[right])`
	`42`	`+`
	`43`	`+ return right`
	`44`	`+`
	`45`	`+ array = [54,26,93,17,77,31,44,55,20]`
	`46`	`+ quick_sort(array)`
	`47`	`+ print(array)`

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