1.循环链表_代码示例
class Node(object): # 创建节点
def __init__(self, item):
self.item = item
self.next = None
class SingleCycLinkedlist(object): # 单向循环链表
def __init__(self):
self._head = None # _head表示私有化
def is_empty(self): # 判空
return self._head == None
def length(self): # 求长度
if self.is_empty():
return 0
count = 1
cur = self._head
while cur.next != self._head:
count += 1
cur = cur.next
return count
def travel(self): # 遍历
if self.is_empty():
return
cur = self._head
print(cur.item)
while cur.next != self._head:
cur = cur.next
print(cur.item, end="")
print("")
def add(self, item): # 头插法
node = Node(item)
if self.is_empty():
self._head = node
node.next = self._head
else: # 添加的节点指向_head
node.next = self._head
cur = self._head # 移到链表尾部，将尾部节点的next指向node
while cur.next != self._head:
cur = cur.next
cur.next = node
self._head = node #_head指向添加node的
def append(self, item): # 尾插法
node = Node(item)
if self.is_empty():
self._head = node
node.next = self._head
else: # 移到链表尾部
cur = self._head
while cur.next != self._head:
cur = cur.next
cur.next = node # 将尾节点指向node
node.next = self._head # 将node指向头节点_head
def insert(self, pos, item): # 定位置插入
if pos <= 0:
self.add(item)
elif pos > (self.length()-1):
self.append(item)
else:
node = Node(item)
cur = self._head
count = 0
while count < (pos-1): # 移动到指定位置的前一个位置
count += 1
cur = cur.next
node.next = cur.next
cur.next = node
def remove(self, item): # 删除节点
if self.is_empty():
return
cur = self._head # 将cur指向头节点
pre = None
if cur.item == item: # 若头节点的元素就是要查找的元素item
if cur.next != self._head: # 如果链表不止一个节点
# 先找到尾节点，将尾节点的next指向第二个节点
while cur.next != self._head:
cur = cur.next
# cur指向了尾节点
cur.next = self._head.next
self._head = self._head.next
else:
self._head = None # 链表只有一个节点
else:
pre = self._head # 第一个节点不是要删除的
while cur.next != self._head:
if cur.item == item:
pre.next = cur.next
return
else:
pre = cur
cur = cur.next
if cur.item == item: # cur 指向尾节点
pre.next = cur.next # 尾部删除
def search(self, item): # 查找
if self.is_empty():
return False
cur = self._head
if cur.item == item:
return True
while cur.next != self._head:
cur = cur.next
if cur.item == item:
return True
return False
if __name__ == "__main__":
ll = SingleCycLinkedlist()
ll.add('a')
ll.add('b')
ll.append('c')
ll.insert(2, 1)
ll.insert(4, 2)
ll.insert(0, 3)
print ("length:",ll.length()) # 输出：length: 6
ll.travel()
print (ll.search('a')) # True
print (ll.search(7)) # 输出：False
ll.remove(1)
print ("length:",ll.length()) # 输出：length: 5
ll.travel()
2.栈_代码示例
class Stack(object): # 栈先进后出 （用顺序表实现，[]）
def __init__(self):
self.items = []
def is_empty(self): # 判空
return self.items == []
def push(self, item): # 加入元素
self.items.append(item)
def pop(self): # 弹出
return self.items.pop()
def peek(self): # 返回栈顶元素
return self.items[len(self.items)-1]
def size(self): # 返回栈的大小
return len(self.items)
if __name__ == "__main__":
stack = Stack()
stack.push("hi")
stack.push("world")
stack.push("bluski")
print(stack.size())
print(stack.peek())
print(stack.pop())
print(stack.pop())
print(stack.pop())
3.队列_代码示例
class Queue(object): # 队列先进先出 （用顺序表实现，[]）
def __init__(self):
self.items = []
def is_empty(self):
return self.items == []
def enqueue(self, item): # 入队
self.items.insert(0,item)
def dequeue(self): # 出队
return self.items.pop()
def size(self): # 队列大小
return len(self.items)
if __name__ == "__main__":
q = Queue()
q.enqueue("how")
q.enqueue("you")
q.enqueue("are")
print(q.size())
print(q.dequeue())
print(q.dequeue())
print(q.dequeue())
4.双端队列_代码示例
class Deque(object): # 双端队列可两端进出
def __init__(self):
self.items = []
def is_empty(self): # 判空
return self.items == []
def add_front(self, item): # 头入队
self.items.insert(0,item)
def add_rear(self, item): # 尾入队
self.items.append(item)
def remove_front(self): # 头删除
return self.items.pop(0)
def remove_rear(self): # 尾删除
return self.items.pop()
def size(self): # 返回队列大小
return len(self.items)
if __name__ == "__main__":
deque = Deque()
deque.add_front(1)
deque.add_front(2)
deque.add_rear(3)
deque.add_rear(4)
print(deque.size())
print(deque.remove_front())
print(deque.remove_front())
print(deque.remove_rear())
print(deque.remove_rear())
