计数、基数和桶排序的Python实现

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计数排序：

#! /usr/bin/env python#coding=utf-8import random,copyfrom collections import defaultdictdef count_sort(lst, key=lambda x: x):    B,C = [], defaultdict(list)    for x in lst:        C[key(x)].append(x)    for k in range(min(C),max(C)+1):        B.extend(C[k])    return Bdef count_sort2(lst):    # sort integers only    B, C = lst[:], defaultdict(int)    for x in lst:        C[x] += 1    for k in range(min(C)+1,max(C)+1):        C[k] = C[k] + C[k-1]    for i in range(len(lst)-1,-1,-1):        B[C[lst[i]]-1] = lst[i]        C[lst[i]] = C[lst[i]] - 1    return B       if  __name__ =='__main__':    lst = [random.randrange(20) for i in range(10)]    lst2 = copy.deepcopy(lst)    print(lst)    lst2.sort()    print(lst2)        lst = count_sort2(lst)    print(lst)

基数排序：

#! /usr/bin/env python#coding=utf-8import random,copydef radix_sort(lst,d):    print("radix sorting...")    for x in range(d):        slots = [[] for _ in range(10)]        for k in lst:            slots[k/(10**x)%10].append(k)        lst = [a for b in slots for a in b]        print(lst)    print("...sorting over!")    return lstif  __name__ =='__main__':    lst = [random.randrange(1000) for i in range(10)]    lst2 = lst[:]    lst2.sort()    print(lst)    print(lst2)        lst = radix_sort(lst,3)    print(lst)

桶排序：

#! /usr/bin/env python#coding=utf-8import random,copydef insert_sort(lst):    for i in range(1,len(lst)):        cur_value = lst[i]        while i > 0 and lst[i-1] > cur_value:            lst[i] = lst[i-1]            i = i - 1        lst[i] = cur_valuedef bucket_sort_helper(lst,n):    # n --> bucket nums    buckets = [[] for _ in range(n)]    for x in lst:        buckets[int(n*x)].append(x)    B = []    for bucket in buckets:        insert_sort(bucket)        B.extend(bucket)    return Bdef bucket_sort(lst):    return bucket_sort_helper(lst,10)    if  __name__ == '__main__':    lst = [int(random.random()*100)/100.0 for i in range(10)]    lst2 = lst[:]    lst2 = sorted(lst2)    print(lst)    print(lst2)        lst = bucket_sort(lst)    print(lst)

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