Python数据结构与算法之链表,无序链表详解

class Node:
    def __init__(self, initdata):
        self.data = initdata  # 数据元素
        self.next = None      # 指向下一节点的引用
    def getData(self):
        return self.data
    def getNext(self):
        return self.next
    def setData(self, newdata):
        self.data = newdata
    def setNext(self, newnext):
        self.next = newnext

class LinkList:
    def __init__(self):
        self.head = None

class LinkList:
    def isEmpty(self):
        return self.head == None

class LinkList:
    def add(self, item):
        temp = Node(item)
        temp.setNext(self.head)
        self.head = temp

class LinkList:
    def length(self):
        current = self.head
        count = 0
        while current != None:
            count = count + 1
            current = current.getNext()
        return count

class LinkList:
    def search(self, item):
        current = self.head
        found = False
        while current != None and not found:
            if current.getData() == item:
                found = True
            else:
                current = current.getNext()
        return found

class LinkList:
    def remove(self, item):
        current = self.head
        previous = None
        found = False
        while not found:
            if current.getData() == item:
                found = True
            else:
                previous = current
                current = current.getNext()
                if current == None:
                	return found
        if previous == None:
            self.head = current.getnext()
        else:
            previous.setNext(current.getNext())

# 构造节点
class Node:
    def __init__(self, initdata):
        self.data = initdata      # 数据元素
        self.next = None          # 指向下一节点的引用（python变量赋值的本质是引用）
    def getData(self):            # 获取节点的数据元素值
        return self.data
    def getNext(self):            # 获取下一节点的引用 若有节点则直接视作为下一节点
        return self.next
    def setData(self, newdata):   # 给节点的数据元素设置值
        self.data = newdata
    def setNext(self, newnext):   # 给节点设置对下一节点的引用
        self.next = newnext

# 构造链表
class LinkList:
    def __init__(self):            # 设置链表的头部指向 无节点时为None 
        self.head = None
    def isEmpty(self):             # 判断链表是否为空（是否有节点）
        return self.head == None
    def add(self, item):           # 给链表增加新节点（从链表头位置增加）
        temp = Node(item)            # 创建节点并对新节点数据元素赋值
        temp.setNext(self.head)      # 新节点指向当前链表中的第一个节点
        self.head = temp             # 链表头指向新节点
    def length(self):               # 计算链表长度（节点个数）
        current = self.head           # 引入current作为指向标识 指向第一个节点 或者None
        count = 0                     # 引入count作为计数变量
        while current != None:        # 当指向标识指向的不是链表末尾的None时
            count = count + 1           # 节点计数加一
            current = current.getNext() # 指向标识向后移动
        return count
    def search(self, item):                   # 搜索链表中节点
        current = self.head                     # 引入current作为指向标识 指向第一个节点
        found = False                           # 引入found作为寻找状态标识
        while current != None and not found:    # 当current没有指向None 并且 未找到节点
            if current.getData() == item:         # 如果current当前指向的节点是寻找的节点
                found = True                        # 找到
            else:                                 # 否则
                current = current.getNext()         # 指向标识向后移动 
        return found
    def remove(self, item):                 # 从链表中移除节点
        current = self.head                   # 引入current指向标识指向第一个节点
        previous = None                       # 引入previous指向标识指向current的上一个节点 所以当current指向第一个节点时 previous初始化指向的是None
        found = False                         # 引入寻找状态标识 寻找需要移除的节点
        while not found:                      # 遍历节点 以找到为循环结束条件
            if current.getData() == item:       # 如果当前节点是目标节点
                found = True                      # 找到
            else:                               # 当前节点不是目标节点
                previous = current                # previous指向当前节点
                current = current.getNext()       # current指向移动到下一个节点
                if current == None:               # 如果到最后都没找到目标节点
                    return found	 
                                              # 搜索过程结束
        if previous == None:                  # 如果previous目前指向的是None 代表current指向的是链表的第一个节点 也就是说删除的目标节点就是第一个节点
            self.head = current.getnext()        # 链表头直接指向None表示删除第一个节点
        else:                                 # 其他情况下
            previous.setNext(current.getNext())  #  当前节点的上一个节点指向当前节点的下一个节点

class Node:
    def __init__(self, initdata):
        self.data = initdata
        self.next = None
    def getData(self):
        return self.data
    def getNext(self):
        return self.next
    def setData(self, newdata):
        self.data = newdata
    def setNext(self, newnext):
        self.next = newnext

class LinkList:
    def __init__(self):
        self.head = None
    def isEmpty(self):
        return self.head == None
    def add(self, item):
        temp = Node(item)
        temp.setNext(self.head)
        self.head = temp
    def length(self):
        current = self.head
        count = 0
        while current != None:
            count = count + 1
            current = current.getNext()
        return count
    def search(self, item):
        current = self.head
        found = False
        while current != None and not found:
            if current.getData() == item:
                found = True
            else:
                current = current.getNext()
        return found
    def remove(self, item):
        current = self.head
        previous = None
        found = False
        while not found:
            if current.getData() == item:
                found = True
            else:
                previous = current
                current = current.getNext()
				if current == None:
					return found
        if previous == None:
            self.head = current.getnext()
        else:
            previous.setNext(current.getNext())