Python笔记——排序算法的实现

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排序算法，目前只实现了七种，后续慢慢会补上~~各位多指教

分别为：

1. 选择排序

2. 插入排序

3. 冒泡排序

4. 归并排序

5. 快速排序

6. 基数排序

7. 计数排序

另外还有希尔，堆，桶排序，以及各种算法的改进版本，需要去处理下

直接贴代码

[python] view plain copy print?

# file :sort.py
import math
class sort:
def selectSort(self,L):
size = len(L)
for i in range(0,size):
max=L[i]
index = i
for j in range(i,size):
if L[j] > max:
max=L[j]
index=j
temp = L[i]
L[i]=max
L[index]=temp
print(L)
def insertSort(self,L):
size = len(L)
for i in range(1,size):
fv = L[i]
j = i
while(j>=1):
if fv < L[j-1]:
L[j] = L[j-1]
else:
break
j=j-1
L[j] = fv
print(L)
def bubbleSort(self,L):
size = len(L)
for i in range(size-1,-1,-1):
for j in range(0,i-1):#这里需要注意下，重新看下是否符合，感觉怪怪的
if L[j]>L[j+1]:
temp = L[j]
L[j]=L[j+1]
L[j+1] = temp
print(L)
def merge(self,L1,L2):
L=[]
index1 = 0
index2 = 0
size1 = len(L1)
size2 = len(L2)
top = min(size1,size2)
while(index1!=size1 and index2!=size2 ):
if L1[index1] > L2[index2]:
L.append(L2[index2])
index2 = index2 + 1
else:
L.append(L1[index1])
index1 = index1 + 1
if index1 < size1:
for i in range(index1,size1):
L.append(L1[i])
if index2 < size2:
for i in range(index2,size2):
L.append(L2[i])
return L
def mergeInL(self,L,first,mid,last):
tempa = []
tempb = []
for i in range(first,mid+1):
tempa.append(L[i])
for i in range(mid+1,last+1):
tempb.append(L[i])
tempc = self.merge(tempa,tempb)
index = 0
for i in range(first,last+1):
L[i] = tempc[index]
index += 1
#我错了。。。本来两个方法，写着写着变三个方法，改天再改
def mergeSort(self,L,first,last):
#print("1first = %d last = %d" %(first,last))
if first < last:
#print("2first = %d last = %d"%(first,last))
mid = math.trunc((first+last)/2) #必须拿到整数,晕死
self.mergeSort(L,first,mid)
self.mergeSort(L,mid+1,last)
self.mergeInL(L,first,mid,last)
#代码简洁效率高~~改天实现改进版的
def quickSort(self,L,left,right):
i = left
j = right
middle = L[left]
while i<=j:
while L[i]<middle and i<right:
i += 1
while L[j]>middle and j>left:
j -= 1
if i<=j: #命中一对
temp = L[i]
L[i] = L[j]
L[j] = temp
i += 1
j += 1
if left<j:
self.quickSort(L,left,j)
if right > i:
self.quickSort(L,i,right)
def __bucketInit(self):
l0 = []
l1 = []
l2 = []
l3 = []
l4 = []
l5 = []
l6 = []
l7 = []
l8 = []
l9 = []
bucket = [l0,l1,l2,l3,l4,l5,l6,l7,l8,l9]
return bucket
#基数排序
def radixSort(self,L):
radix = 10
base = 1
bucket = self.__bucketInit()
max = L[0]
for i in L:
if i > max:
max = i
while math.trunc((max%radix)/base) > 0:
#放到桶里
for i in L:
index = math.trunc((i%radix)/base)
bucket[index].append(i)
#重新整理回L
L = []
for i in bucket:
L.extend(i)
bucket = self.__bucketInit()
print(L)
#下一轮循环取下一位
radix *= 10
base *=10
return L
#计数排序
def countSort(self,L):
size = len(L)
min = max = L[0]
#拿到最大和最小
for i in L:
if i<min:
min = i
if i>max:
max = i
#得到数字的区间
bound = max - min +1
#初始化计数数组
count =[]
for i in range(0,bound):
count.append(0)
#统计每个数出现的次数，放到count中
for i in range(0,size):
count[ L[i]-min ] +=1
z = 0
print("min = %d and max = %d"%(min,max))
for i in range(min,max+1):
#print("i="+str(i))
for j in range(0,count[i-min]):#count[i-min]表示该数字出现次数，0次地话不处理，多次的话依次插入
#print("j="+str(j))
L[z] = i
print(L)
z+=1
print(L)
a = sort()
l = [3,2,5,7,1,9]
print('原始数组')
print(l)
print('选择排序')
a.selectSort(l)
l2 = [3,2,5,7,1,9]
print('插入排序')
a.insertSort(l2)
print('冒泡排序')
l3 = [3,2,5,7,1,9]
a.bubbleSort(l3)
print('列表归并算法没有问题')
la = [1,3,5,7,9,11]
lb = [2,4,6,8]
print(a.merge(la,lb))
print('归并排序')
lm = [3,2,5,7,1,9]
a.mergeSort(lm,0,5)
print(lm)
print('快速排序')
lq = [3,2,5,7,1,9]
a.quickSort(lq,0,5)
print(lq)
print('基数排序')
lr = [3,20,5,713,1,9]
print(lr)
a.radixSort(lr)
print("计数排序")
lz = [3,2,5,7,1,9]
a.countSort(lz)

运行结果:

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