二叉树简单实现

二叉树简单实现：

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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二叉树简单实现：

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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