python实现排序算法

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##冒泡排序

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def bubble(nums):
    for i in range(len(nums)-1):
        for j in range(len(nums)-i-1):
            if nums[j] > nums[j+1]:
                nums[j],nums[j+1] = nums[j+1],nums[j]
    return nums

##插入排序

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def insert_sort(arr):
	for i in range(1,len(arr)):
		key = arr[i]
		j = i-1
		while j>0 and key < arr[j]:
			arr[j+1] = arr[j]
			j -= 1
		arr[j+1] = key

##归并排序

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def merge_sort(alist):
	if len(alist) <= 1:
		return alist
	nums = len(alist)/2
	left = merge_sort(alist[:num])
	right = merge_sort(alist[num:]
	return merge(left,right)
def merge(left,right):
	l,r = 0,0
	result = []
	while l<len(left) and r<len(right):
		if left[1] < right[r]
			result.append(left[1])
			l+=1
		else:
			result.append(right[r])
			r+=1
	result += left[l:]
	result += rifht[r:]
	return result

##快速排序

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def quick_sort(alist,start,end):
    if start >= end:
        return
    mid = alist[start]
    low = start
    high = end
    while low < high:
        while low < high and alist[high] >= mid:
            high -= 1
        alist[low] = alist[high]
        while low < high and alist[low] < mid:
            low+=1
        alist[high] = alist[low]
    alist[low] = mid
    quick_sort(alist,start,low-1)
    quick_sort(alist,low+1,end)