1、直接插入排序
def insert_sort(alist):
"""插入排序"""
n = len(alist)
for j in range(1,n):
i = j
while i > 0:
if alist[i] < alist[i-1]:
alist[i],alist[i-1] = alist[i-1],alist[i]
i -= 1
else:
break
if __name__ == "__main__":
l = [451, 122, 12, 455, 48, 48, 524, 65, 99, 1225]
print(l)
insert_sort(l)
print(l)
2、希尔排序
#Author:liuyang
def shell_sort(alist):
"""希尔排序"""
n = len(alist)
gap = n // 2
while gap > 0:
#插入算法，唯一的区别就是gap
for j in range(gap,n):
i = j
while i > 0:
if alist[i] < alist[i - gap]:
alist[i], alist[i - gap] = alist[i - gap], alist[i]
i -= gap
else:
break
gap //= 2
if __name__ == "__main__":
l = [451, 122, 12, 455, 48, 48, 524, 65, 99, 1225]
print(l)
shell_sort(l)
print(l)
3、直接选择排序
# Author:liuyang
def select_sort(alist):
"""选择排序"""
n = len(alist)
for j in range(0, n - 1): # j 0 ~ n-2
min_index = j
for i in range(j + 1, n):
if alist[min_index] > alist[i]:
min_index = i
alist[j], alist[min_index] = alist[min_index], alist[j]
4、冒泡排序
#Author:liuyang
def bubble_sort(alist):
"""冒泡排序"""
n = len(alist)
for j in range(0,n-1): #产生0到n-2,一共n-1个数
count = 0
for i in range(0,n-1-j):
if alist[i] > alist[i+1]:
alist[i],alist[i+1] = alist[i+1],alist[i]
count += 1
if count == 0:
return
# i 0 ~ n-2 range(0,n-1) j = 0
# i 0 ~ n-3 range(0,n-1-1) j = 1
# i 0 ~ n-4 range(0,n-1-2) j = 2
# j = n range(0,n-1-j)
if __name__ == "__main__":
l = [451, 122, 12, 455, 48, 48, 524, 65, 99, 1225]
print(l)
bubble_sort(l)
print(l)
5、快速排序
#Author:liuyang
def quick_sort(alist,first,last):
"""快速排序"""
if first >= last:
return
mid_value = alist[first]
low = first
high = last
while low < high:
while low < high and alist[high] >= mid_value:
high -= 1
alist[low] = alist[high]
while low < high and alist[low] < mid_value:
low += 1
alist[high] = alist[low]
alist[low] = mid_value
#对左边进行快速排序
quick_sort(alist,first,low-1)
#对右边进行快速排序
quick_sort(alist,high+1,last)
if __name__ == "__main__":
l = [451, 122, 12, 455, 48, 48, 524, 65, 99, 1225]
print(l)
quick_sort(l,0,len(l)-1)
print(l)
#Author:liuyang
def quick_sort(alist):
if len(alist) < 2:
return alist #基线条件
else:
pivot = alist[0]
less = [i for i in alist[1:] if i <= pivot] #所有小于基准值的子数组
greater = [i for i in alist[1:] if i > pivot] #所有大于基准值的子数组
return quick_sort(less) + [pivot] + quick_sort(greater)
if __name__ == "__main__":
l = [451, 122, 12, 455, 48, 48, 524, 65, 99, 1225]
print(l)
print(quick_sort(l))
6、归并排序
#Author:liuyang
def merge_sort(alist):
"""归并排序"""
n = len(alist)
if n == 1:
return alist
mid = n // 2
left_li = merge_sort(alist[:mid])
right_li = merge_sort(alist[mid:])
left_point,right_point = 0,0
result = []
while left_point < len(left_li) and right_point < len(right_li):
if left_li[left_point] < right_li[right_point]:
result.append(left_li[left_point])
left_point += 1
else:
result.append(right_li[right_point])
right_point += 1
result += left_li[left_point:]
result += right_li[right_point:]
return result
if __name__ == "__main__":
l = [451, 122, 12, 455, 48, 48, 524, 65, 99, 1225]
print(l)
new_list = merge_sort(l)
print(l)
print(new_list)
另附大佬实现的各种排序代码（此代码来源于：数据结构与算法 Python语言描述 作者：裘宗燕）
""" 排序算法
"""
from random import randrange, randint
class Record:
def __init__(self, key, datum):
self.key = key
self.datum = datum
def __str__(self):
return "R(" + str(self.key) + ", " + str(self.datum) + ")"
def printR(lst):
print("[" + ", ".join(map(str, lst)) + "]")
#### 简单插入排序
##def insert_sort(lst) :
## for i in range(1, len(lst)): # 开始时片段[0:1]已排序
## x = lst[i]
## j = i
## while j > 0 and lst[j-1].key > x.key:
## lst[j] = lst[j-1] # 反序逐个后移元素至确定插入位置
## j -= 1
## lst[j] = x
##
##
##def test1(n):
## l1 = [Record(randint(1, 20), i) for i in range(n)]
## printR(l1)
## insert_sort(l1)
## printR(l1)
#### 简单选择排序
# def select_sort(lst):
# for i in range(len(lst)-1):
# k = i
# for j in range(i, len(lst)):
# if lst[j].key < lst[k].key:
# k = j
# if i != k:
# lst[i], lst[k] = lst[k], lst[i]
#
#
# def test2(n):
# l1 = [Record(randint(1, 20), i) for i in range(n)]
# printR(l1)
# select_sort(l1)
# printR(l1)
#### 简单起泡排序
##def bubble_sort(lst):
## for i in range(len(lst)):
## for j in range(1, len(lst)-i):
## if lst[j-1].key > lst[j].key:
## lst[j-1], lst[j] = lst[j], lst[j-1]
#### 起泡排序，无逆序时提前结束
# def bubble_sort(lst):
# for i in range(len(lst)):
# found = False
# for j in range(1, len(lst)-i):
# if lst[j-1].key > lst[j].key:
# lst[j-1], lst[j] = lst[j], lst[j-1]
# found = True
# if not found:
# break
#
#
# def test3(n):
# l1 = [Record(randint(1, 20), i) for i in range(n)]
# printR(l1)
# bubble_sort(l1)
# printR(l1)
#### 快速排序
# def quick_sort(lst):
# def qsort_rec(lst, l, r):
# if l >= r:
# return # 分段中无记录或只有一个记录
# i, j = l, r
# pivot = lst[i]
# while i < j: # 找 pivot 的最终位置
# while i < j and lst[j].key >= pivot.key:
# j -= 1 # 用 j 向左找小于 pivot 的记录移到左边
# if i < j:
# lst[i] = lst[j]
# i += 1
# while i < j and lst[i].key <= pivot.key:
# i += 1 # 用 i 向右找大于 pivot 的记录移到右边
# if i < j:
# lst[j] = lst[i]
# j -= 1
# lst[i] = pivot # 将 pivot 存入其最终位置
# qsort_rec(lst, l, i-1) # 递归处理左半区间
# qsort_rec(lst, i+1, r) # 递归处理右半区间
#
# qsort_rec(lst, 0, len(lst)-1) # 主函数调用 qsort_rec
#
#
# def test4(n):
# l1 = [Record(randint(1, 20), i) for i in range(n)]
# printR(l1)
# quick_sort(l1)
# printR(l1)
#### 快速排序的另一种实现
# def quick_sort1(lst):
# def qsort(lst, begin, end):
# if begin >= end:
# return
# pivot = lst[begin].key
# i = begin
# for j in range(begin + 1, end + 1):
# if lst[j].key < pivot: # 发现一个小元素
# i += 1
# lst[i], lst[j] = lst[j], lst[i] # 小元素交换到前面
# lst[begin], lst[i] = lst[i], lst[begin] # 枢轴元素就位
# qsort(lst, begin, i - 1)
# qsort(lst, i + 1, end)
#
# qsort(lst, 0, len(lst) - 1)
#
#
# def test4(n):
# l1 = [Record(randint(1, 20), i) for i in range(n)]
# printR(l1)
# quick_sort1(l1)
# printR(l1)
#### 归并排序
# def merge_sort(lst):
# slen, llen = 1, len(lst)
# templst = [None] * llen
# while slen <= llen:
# merge_pass(lst, templst, llen, slen)
# slen *= 2
# merge_pass(templst, lst, llen, slen) # 结果存回原位
# slen *= 2
#
#
# def merge_pass(lfrom, lto, llen, slen):
# i = 0
# while i + 2 * slen < llen: # 归并长slen的两段
# merge(lfrom, lto, i, i + slen, i + 2 * slen)
# i += 2 * slen
# if i + slen < llen: # 剩下两段，后段长度小于slen
# merge(lfrom, lto, i, i + slen, llen)
# else: # 只剩下一段，复制到表lto
# for j in range(i, llen):
# lto[j] = lfrom[j]
#
#
# def merge(lfrom, lto, low, m, high):
# i, j, k = low, m, low
# while i < m and j < high: # 反复复制两段首记录中较小的
# if lfrom[i].key <= lfrom[j].key:
# lto[k] = lfrom[i]
# i += 1
# else:
# lto[k] = lfrom[j]
# j += 1
# k += 1
# while i < m: # 复制第一段剩余记录
# lto[k] = lfrom[i]
# i += 1
# k += 1
# while j < high: # 复制第二段剩余记录
# lto[k] = lfrom[j]
# j += 1
# k += 1
#
#
# def test5(n):
# l1 = [Record(randint(1, 20), i) for i in range(n)]
# printR(l1)
# merge_sort(l1)
# printR(l1)
#### 基数排序
#### 假设被排序仍是以记录类型 Record 为元素的表，其中
#### 关键码是数字 0 到 9 的序列（元组），长度 r 为参数
#### 排序中用 10 个 list 存储各关键码元素对应的序列
#### 一遍分配后收集回到原表，r 遍分配和收集完成排序工作
# def radix_sort(lst, r):
# rlists = [[] for i in range(10)]
# llen = len(lst)
# for d in range(-1, -r-1, -1):
# for j in range(llen):
# rlists[lst[j].key[d]].append(lst[j])
# j = 0
# for i in range(10):
# tmp = rlists[i]
# for k in range(len(tmp)):
# lst[j] = tmp[k]
# j += 1
# rlists[i].clear()
#
#
# def test6(n):
# lst = [Record(tuple((randrange(10) for j in range(3))),
# i) for i in range(n)]
# printR(lst)
# radix_sort(lst, 3)
# printR(lst)
# print()
# if __name__ == '__main__':
# test1(15)
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