計數排序Counting sort 原理：
https://blog.csdn.net/weililansehudiefei/article/details/71941188
my stupid code:
# -*- coding: utf-8 -*-
"""
Created on Wed Aug 14 14:47:01 2019
@author: zhang
"""
import numpy as np
def counting_sort(data):
data_num = len(data)
data_index = [0]*data_num
data_final = list(np.full([data_num], np.nan))
for i in range(data_num):
for j in range(data_num):
if i!=j and data[i]>data[j]:
data_index[i] = data_index[i]+1
data_temp = data_final[data_index[i]]
while np.isnan(data_temp)==False: #if data list have two same data
data_index[i] = data_index[i]+1
data_temp = data_final[data_index[i]]
data_final[data_index[i]] = data[i]
return data_final
if __name__ =='__main__':
data = [10,20,50,3,5,7,9,11,88,55,77,56,1,2,4,555,19, 25, 26, 29 ,38 ,50 ,80, 91 ,86, 78 ,66 ,46, 32 ,19 ,15 , 7]
#data = [8,4, 3, 7, 6, 5, 2 ,1,1]
data_num = len(data)
data = counting_sort(data)
answer:
"""
This is pure python implementation of counting sort algorithm
For doctests run following command:
python -m doctest -v counting_sort.py
or
python3 -m doctest -v counting_sort.py
For manual testing run:
python counting_sort.py
"""
from __future__ import print_function
def counting_sort(collection):
"""Pure implementation of counting sort algorithm in Python
:param collection: some mutable ordered collection with heterogeneous
comparable items inside
:return: the same collection ordered by ascending
Examples:
>>> counting_sort([0, 5, 3, 2, 2])
[0, 2, 2, 3, 5]
>>> counting_sort([])
[]
>>> counting_sort([-2, -5, -45])
[-45, -5, -2]
"""
# if the collection is empty, returns empty
if collection == []:
return []
# get some information about the collection
coll_len = len(collection)
coll_max = max(collection)
coll_min = min(collection)
# create the counting array
counting_arr_length = coll_max + 1 - coll_min
counting_arr = [0] * counting_arr_length
# count how much a number appears in the collection
for number in collection:
counting_arr[number - coll_min] += 1
# sum each position with it's predecessors. now, counting_arr[i] tells
# us how many elements <= i has in the collection
for i in range(1, counting_arr_length):
counting_arr[i] = counting_arr[i] + counting_arr[i-1]
# create the output collection
ordered = [0] * coll_len
# place the elements in the output, respecting the original order (stable
# sort) from end to begin, updating counting_arr
for i in reversed(range(0, coll_len)):
ordered[counting_arr[collection[i] - coll_min]-1] = collection[i]
counting_arr[collection[i] - coll_min] -= 1
return ordered
def counting_sort_string(string):
return ''.join([chr(i) for i in counting_sort([ord(c) for c in string])])
if __name__ == '__main__':
# Test string sort
assert "eghhiiinrsssttt" == counting_sort_string("thisisthestring")
try:
raw_input # Python 2
except NameError:
raw_input = input # Python 3
user_input = raw_input('Enter numbers separated by a comma:\n').strip()
unsorted = [int(item) for item in user_input.split(',')]
print(counting_sort(unsorted))