python实现简单算法

#选择n^2
def selectSort(li):
    for i in range(len(li)-1):
        minLoc = i
        for j in range(i+1,len(li)):
            if li[j] < li[minLoc]:
                li[minLoc],li[j] = li[j],li[minLoc]

# li = [2,1,6,8,3,9,424,243,351,51]
# selectSort(li)
# print(li)

#冒泡n^2

def bubbleSort(li):
    for i in range(len(li)-1):
        flag = False
        for j in range(len(li)-i-1):
            if li[j+1] < li[j]:
                li[j+1],li[j] = li[j],li[j+1]
                flag = True
            if not flag:
                return

#插入n^2
def insertSort(li):
    for i in range(1,len(li)):
        tmp = li[i]
        j = i-1
        while j>=0 and li[j] >tmp:
            li[j+1] = li[j]
            j = j-1
        li[j+1] = tmp

# insertSort(li)
# print(li)

#冒泡是把最大的放到最后面，选择是把最小的放前面，插入

#快速排序,nlogn

def partition(li,left,right):
    tmp = li[left]
    while left < right:
        while left < right and tmp <= li[right]:
            right = right - 1
        li[left] = li[right]

        while left < right and tmp >= li[left]:
            left = left + 1
        li[right] = li[left]
    li[left] = tmp
    return left

def quickSort(li,left,right):
    if left <right:
        mid = partition(li,left,right)
        quickSort(li,left,mid-1)
        quickSort(li,mid+1,right)


#归并排序nlogn

def merge(li,low,mid,high):
    i = low
    j = mid + 1
    ltmp = []
    while i <= mid and j<=high:
        if li[i] >= li[j]:
            ltmp.append(li[j])
            j = j+1
        else:
            ltmp.append(li[i])
            i = i+1
    while i<= mid:
        ltmp.append(li[i])
        i = i+1
    while j<=high:
        ltmp.append(li[j])
        j = j+1
    li[low:high+1] = ltmp

def mergeSort(li,low,high):
    if low < high:
        mid = (low + high) //2
        mergeSort(li,low,high)
        mergeSort(li,mid+1,high)
        merge(li,low,mid,high)
        print(li[low:high+1])

li = [10,4,6,3,8,2,5,7]
# mergeSort(li,0,len(li)-1)


#计数排序O(n)
def countSort(li):
    count = [0 for i in range(11)]

    for x in li:
        count[x] +=1
    li.clear()

    for index,val in enumerate(count):
        for i in range(val):
            li.append(index)

# countSort(li)
# print(li)


#二分法
def BinarySearch(n,l):
    print(l)
    if len(l) == 0:
        print('not exists')
        return
    mid_index = len(l) // 2
    if n > l[mid_index]:
        l = l[mid_index+1:]
        BinarySearch(n,l)
    elif n < l[mid_index]:
        l = l[:mid_index]
        BinarySearch(n,l)
    else:
        print(f'find it,index is l[{l.index(n)}]')

# BinarySearch(6,li)