Python数据结构

  1 class Node(object):
  2     def __init__(self, elem):
  3         self.elem = elem
  4         self.next = None
  5 
  6 
  7 class SingleLinkList(object):
  8     def __init__(self, node=None):
  9         self.__head = node
 10 
 11     def is_empty(self):
 12         return self.__head == None
 13 
 14     def length(self):
 15         """
 16         链表长度
 17         :return:
 18         """
 19         # 用来移动遍历节点
 20         cur = self.__head
 21         count = 0
 22         while cur:
 23             cur = cur.next
 24             count += 1
 25         return count
 26 
 27     def travel(self):
 28         """
 29         遍历链表长度
 30         :return:
 31         """
 32         cur = self.__head
 33         while cur:
 34             print(cur.elem, end=‘ ‘)
 35             # print(cur.elem)
 36             cur = cur.next
 37 
 38     def append(self, item):
 39         """
 40         尾部插入
 41         进来先判断是否为空
 42         为空的话 头指针指向插入节点即可
 43         否则需要遍历到尾结点再插入
 44         :return:
 45         """
 46         node = Node(item)
 47 
 48         if self.is_empty():
 49             self.__head = node
 50         else:
 51             cur = self.__head
 52             while cur.next:
 53                 cur = cur.next
 54             cur.next = node
 55 
 56     def insert(self, pos, item):
 57         """
 58         指定位置添加元素
 59         :param pos: 添加的位置
 60         :param item: 添加的元素
 61         :return:
 62         先对pos进行判断，如果小于0 那么赋值为
 63         如果大于最大长度 那么放在最后面
 64         """
 65         # 实例化要插入的点
 66         node = Node(item)
 67         if pos <= 0:
 68             pos = 0
 69         if pos >= self.length() - 1:
 70             pos = self.length() - 1
 71 
 72         pre = self.__head
 73         count = 0
 74         while count < pos - 1:
 75             count += 1
 76             pre = pre.next
 77 
 78         node.next = pre.next
 79         pre.next = node
 80 
 81     def add(self, item):
 82         """
 83         头插法
 84         :param item:添加的是数字，需要实例化成对象
 85         :return:
 86         """
 87         node = Node(item)
 88         node.next = self.__head
 89         self.__head = node
 90 
 91     def remove(self, item):
 92         pre = self.__head
 93         # 要遍历到需要删除节点的前一个节点
 94         while pre.next:
 95             # 这里面还需要对删除第一个元素做单独处理
 96             if item == pre.elem:
 97                 self.__head = pre.next
 98                 break
 99             else:
100                 # 处理中间和后面的元素
101                 if pre.next.elem == item:
102                     pre.next = pre.next.next
103                 else:
104                     pre = pre.next
105 
106     def search(self, item):
107         """
108         全部遍历一遍
109         :param item:
110         :return:
111         """
112         cur = self.__head
113         while cur:
114             if cur.elem == item:
115                 return True
116             else:
117                 cur = cur.next
118         return False
119 
120 
121 if __name__ == "__main__":
122     ll = SingleLinkList()
123     print(ll.is_empty())
124     ll.append(100)
125     ll.append(200)
126     ll.add(10)
127     ll.append(300)
128     ll.append(400)
129     ll.travel()
130     print("")
131     print(ll.length())
132     ll.insert(2, 1000)
133     ll.travel()
134     print("")
135     ll.remove(400)
136     ll.travel()
137     print()
138     print(ll.search(140))
139     print(ll.search(1000))
140 """
141 True
142 10 100 200 300 400 
143 5
144 10 100 1000 200 300 400 
145 10 100 1000 200 300 
146 False
147 True
148 """