Python编程实现双链表，栈，队列及二叉树的方法示例

这篇文章主要介绍了Python编程实现双链表，栈，队列及二叉树的方法,结合具体实例形式分析了Python简单实现数据结构中双链表，栈，队列及二叉树相关操作技巧,需要的朋友可以参考下

本文实例讲述了Python编程实现双链表，栈，队列及二叉树的方法。分享给大家供大家参考，具体如下：

1.双链表

class Node(object): def __init__(self, value=None): self._prev = None self.data = value self._next = None def __str__(self): return "Node(%s)"%self.data class DoubleLinkedList(object): def __init__(self): self._head = Node() def insert(self, value): element = Node(value) element._next = self._head self._head._prev = element self._head = element def search(self, value): if not self._head._next: raise ValueError("the linked list is empty") temp = self._head while temp.data != value: temp = temp._next return temp def delete(self, value): element = self.search(value) if not element: raise ValueError('delete error: the value not found') element._prev._next = element._next element._next._prev = element._prev return element.data def __str__(self): values = [] temp = self._head while temp and temp.data: values.append(temp.data) temp = temp._next return "DoubleLinkedList(%s)"%values

2. 栈

class Stack(object): def __init__(self): self._top = 0 self._stack = [] def put(self, data): self._stack.insert(self._top, data) self._top += 1 def pop(self): if self.isEmpty(): raise ValueError('stack 为空') self._top -= 1 data = self._stack[self._top] return data def isEmpty(self): if self._top == 0: return True else: return False def __str__(self): return "Stack(%s)"%self._stack

3.队列

class Queue(object): def __init__(self, max_size=float('inf')): self._max_size = max_size self._top = 0 self._tail = 0 self._queue = [] def put(self, value): if self.isFull(): raise ValueError("the queue is full") self._queue.insert(self._tail, value) self._tail += 1 def pop(self): if self.isEmpty(): raise ValueError("the queue is empty") data = self._queue.pop(self._top) self._top += 1 return data def isEmpty(self): if self._top == self._tail: return True else: return False def isFull(self): if self._tail == self._max_size: return True else: return False def __str__(self): return "Queue(%s)"%self._queue

4. 二叉树（定义与遍历）

class Node: def __init__(self,item): self.item = item self.child1 = None self.child2 = None class Tree: def __init__(self): self.root = None def add(self, item): node = Node(item) if self.root is None: self.root = node else: q = [self.root] while True: pop_node = q.pop(0) if pop_node.child1 is None: pop_node.child1 = node return elif pop_node.child2 is None: pop_node.child2 = node return else: q.append(pop_node.child1) q.append(pop_node.child2) def traverse(self): # 层次遍历 if self.root is None: return None q = [self.root] res = [self.root.item] while q != []: pop_node = q.pop(0) if pop_node.child1 is not None: q.append(pop_node.child1) res.append(pop_node.child1.item) if pop_node.child2 is not None: q.append(pop_node.child2) res.append(pop_node.child2.item) return res def preorder(self,root): # 先序遍历 if root is None: return [] result = [root.item] left_item = self.preorder(root.child1) right_item = self.preorder(root.child2) return result + left_item + right_item def inorder(self,root): # 中序序遍历 if root is None: return [] result = [root.item] left_item = self.inorder(root.child1) right_item = self.inorder(root.child2) return left_item + result + right_item def postorder(self,root): # 后序遍历 if root is None: return [] result = [root.item] left_item = self.postorder(root.child1) right_item = self.postorder(root.child2) return left_item + right_item + result t = Tree() for i in range(10): t.add(i) print('层序遍历:',t.traverse()) print('先序遍历:',t.preorder(t.root)) print('中序遍历:',t.inorder(t.root)) print('后序遍历:',t.postorder(t.root))

输出结果：

层次遍历: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] 先次遍历: [0, 1, 3, 7, 8, 4, 9, 2, 5, 6] 中次遍历: [7, 3, 8, 1, 9, 4, 0, 5, 2, 6] 后次遍历: [7, 8, 3, 9, 4, 1, 5, 6, 2, 0]

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