Python常见排序算法实现与测速源码，python测速,Python常见排序算法

Python常见排序算法实现与测速源码，python测速,Python常见排序算法

Python常见排序算法实现与测速，是Python算法相关，测试排序方法看看哪个Python排序方法的执行速度最快。本文为大家提供了用Python来实现各种排序算法的性能测试的源码详解与下载。

好的排序算法，不但是要准确计算出结果，更要在保证结果正确的前提下更加的节省时间。所以来为python常见排序算法做个测速是很有必要的。

源码中需要用到random与time模块方法。

import random import time    DEBUG = False N = 1000     # number of elements in listlist1 = []   # list of integer elementsfor i in range(0, N):    list1.append(random.randint(0, N-1))def print_timing(func):    def wrapper(*arg):        t1 = time.clock()        res = func(*arg)        t2 = time.clock()        print '%s took %0.3fms' % (func.func_name, (t2-t1)*1000.0)        return res    return wrapper@print_timingdef adaptive_merge_sort(list2):    """adaptive merge sort, built into Python since version 2.3"""    list2.sort()@print_timingdef bubble_sort(list2):    swap_test = False    for i in range(0, len(list2) - 1):        for j in range(0, len(list2) - i - 1):            if list2[j] > list2[j + 1]:                list2[j], list2[j + 1] = list2[j + 1], list2[j]  # swap            swap_test = True        if swap_test == False:            break@print_timingdef selection_sort(list2):    for i in range(0, len (list2)):        min = i        for j in range(i + 1, len(list2)):            if list2[j] < list2[min]:                min = j        list2[i], list2[min] = list2[min], list2[i]       @print_timingdef insertion_sort(list2):    for i in range(1, len(list2)):        save = list2[i]        j = i        while j > 0 and list2[j - 1] > save:            list2[j] = list2[j - 1]            j -= 1        list2[j] = save  @print_timingdef quick_sort(list2):    quick_sort_r(list2, 0, len(list2) - 1)def quick_sort_r(list2 , first, last):    if last > first:        pivot = partition(list2, first, last)        quick_sort_r(list2, first, pivot - 1)        quick_sort_r(list2, pivot + 1, last)def partition(list2, first, last):    sred = (first + last)/2    if list2[first] > list2 [sred]:        list2[first], list2[sred] = list2[sred], list2[first]  # swap    if list2[first] > list2 [last]:        list2[first], list2[last] = list2[last], list2[first]  # swap    if list2[sred] > list2[last]:        list2[sred], list2[last] = list2[last], list2[sred]    # swap    list2 [sred], list2 [first] = list2[first], list2[sred]    # swap    pivot = first    i = first + 1    j = last      while True:        while i <= last and list2[i] <= list2[pivot]:            i += 1        while j >= first and list2[j] > list2[pivot]:            j -= 1        if i >= j:            break        else:            list2[i], list2[j] = list2[j], list2[i]  # swap    list2[j], list2[pivot] = list2[pivot], list2[j]  # swap    return j#www.iplaypy.com@print_timingdef heap_sort(list2):    first = 0    last = len(list2) - 1    create_heap(list2, first, last)    for i in range(last, first, -1):        list2[i], list2[first] = list2[first], list2[i]         establish_heap_property (list2, first, i - 1)def create_heap(list2, first, last):    i = last/2    while i >= first:        establish_heap_property(list2, i, last)        i -= 1def establish_heap_property(list2, first, last):    while 2 * first + 1 <= last:        k = 2 * first + 1        if k < last and list2[k] < list2[k + 1]:            k += 1        if list2[first] >= list2[k]:            break        list2[first], list2[k] = list2[k], list2[first]          first = k@print_timingdef merge_sort(list2):    merge_sort_r(list2, 0, len(list2) -1)def merge_sort_r(list2, first, last):    if first < last:        sred = (first + last)/2        merge_sort_r(list2, first, sred)        merge_sort_r(list2, sred + 1, last)        merge(list2, first, last, sred)def merge(list2, first, last, sred):    helper_list = []    i = first    j = sred + 1    while i <= sred and j <= last:        if list2 [i] <= list2 [j]:            helper_list.append(list2[i])            i += 1        else:            helper_list.append(list2 [j])            j += 1    while i <= sred:        helper_list.append(list2[i])        i +=1    while j &l2000t;= last:        helper_list.append(list2[j])        j += 1    for k in range(0, last - first + 1):        list2[first + k] = helper_list [k]def print10(list2):    for k in range(10):        print list2[k],    printif __name__ == "__main__" :    print "timing 7 sorting algorithms with a list of 1000 integers:"       list2 = list(list1)    adaptive_merge_sort(list2)    if DEBUG:        print10(list2)    list2 = list(list1)    bubble_sort(list2)    if DEBUG:        print10(list2)    list2 = list(list1)    heap_sort(list2)    if DEBUG:        print10(list2)    list2 = list(list1)    insertion_sort(list2)    if DEBUG:        print10(list2)    list2 = list(list1)    merge_sort(list2)    if DEBUG:        print10(list2)    list2 = list(list1)    quick_sort(list2)    if DEBUG:        print10(list2)    list2 = list(list1)    selection_sort(list2)    if DEBUG:        print10(list2)    # final test    list2 = list(list1)    if DEBUG:        print "final test: ",        print10(list2)   

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