算法与数据结构Python书

《算法与数据结构Python书》是一本介绍Python编程语言中算法和数据结构的书籍。该书主要分为两个部分，第一部分介绍了Python编程语言的基础知识，包括Python的数据类型、控制流、函数、模块等内容。第二部分则介绍了Python中常用的算法和数据结构，包括数组、链表、栈、队列、树、图等。

以下是该书中的一些例子：

1.使用Python实现二分查找算法

def binary_search(arr, x):
    low = 0
    high = len(arr) - 1
    mid = 0
 
    while low <= high:
 
        mid = (high + low) // 2
 
        if arr[mid] < x:
            low = mid + 1
 
        elif arr[mid] > x:
            high = mid - 1
 
        else:
            return mid
 
    return -1

2.使用Python实现快速排序算法

def quicksort(arr):
    if len(arr) <= 1:
        return arr
    else:
        pivot = arr[0]
        less = [x for x in arr[1:] if x <= pivot]
        greater = [x for x in arr[1:] if x > pivot]
        return quicksort(less) + [pivot] + quicksort(greater)

3.使用Python实现哈希表数据结构

class HashTable:
    def __init__(self):
        self.size = 11
        self.slots = [None] * self.size
        self.data = [None] * self.size

    def put(self, key, data):
        hashvalue = self.hashfunction(key,len(self.slots))

        if self.slots[hashvalue] == None:
            self.slots[hashvalue] = key
            self.data[hashvalue] = data
        else:
            if self.slots[hashvalue] == key:
                self.data[hashvalue] = data  #replace
            else:
                nextslot = self.rehash(hashvalue, len(self.slots))
                while self.slots[nextslot] != None and \
                                self.slots[nextslot] != key:
                    nextslot = self.rehash(nextslot, len(self.slots))

                if self.slots[nextslot] == None:
                    self.slots[nextslot]=key
                    self.data[nextslot]=data
                else:
                    self.data[nextslot] = data #replace

    def hashfunction(self,key,size):
        return key%size

    def rehash(self,oldhash,size):
        return (oldhash+1)%size

    def get(self,key):
        startslot = self.hashfunction(key,len(self.slots))

        data = None
        stop = False
        found = False
        position = startslot
        while self.slots[position] != None and  \
                             not found and not stop:
            if self.slots[position] == key:
                found = True
                data = self.data[position]
            else:
                position=self.rehash(position,len(self.slots))
                if position == startslot:
                    stop = True
        return data

    def __getitem__(self,key):
        return self.get(key)

    def __setitem__(self,key,data):
        self.put(key,data)