11.二叉树

Posted bobo-zhang

tags:

篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了11.二叉树相关的知识,希望对你有一定的参考价值。

python实现二叉树的数据结构:

  . 二叉树的排序方式:

    - 广度遍历(层次遍历)

    - 深度遍历:
      - 前序(根左右):把根放到最前面
      - 中序(左根右):把根放到中间
      - 后序(左右根):把根放到最后

class Node():
    def __init__(self,item):
        self.item = item
        self.right = None
        self.left = None
class Tree():
    def __init__(self):
        self.root = None
    def add(self,item):
        node = Node(item)
        if self.root is None:
            self.root = node
            return
        else:
            queue = [self.root]
            while queue:
                cur = queue.pop(0)
                if cur.left is None:
                    cur.left = node
                    return
                else:
                    queue.append(cur.left)
                if cur.right is None:
                    cur.right = node
                    return
                else:
                    queue.append(cur.right)
    #广度遍历
    def travel(self):
        if self.root is None:
            print(‘‘)
            return
        else:
            queue = [self.root]
            while queue:
                cur = queue.pop(0)
                print(cur.item)
                if cur.left is not None:
                    queue.append(cur.left)
                if cur.right is not None:
                    queue.append(cur.right)
                    
    #深度遍历:前序,中序,后序遍历
    def forwordTravel(self,root):
        if root is None:
            return
        print(root.item,end= )
        self.forwordTravel(root.left)
        self.forwordTravel(root.right)
        
    def middleTravel(self,root):
        if root is None:
            return
        self.middleTravel(root.left)
        print(root.item,end= )
        self.middleTravel(root.right)
        
    def backTravel(self,root):
        if root is None:
            return
        self.backTravel(root.left)
        self.backTravel(root.right)
        print(root.item,end= )
                
tree = Tree()
tree.add(0)
tree.add(1)
tree.add(2)
tree.add(3)
tree.add(4)
tree.add(5)
tree.add(6)
tree.add(7)
tree.add(8)
tree.add(9)

tree.travel()
tree.forwordTravel(tree.root)
print(\n)
tree.backTravel(tree.root)
print(\n)
tree.middleTravel(tree.root)
print(\n)

 

python实现排序二叉树:

#排序二叉树
class Node():
    def __init__(self,item):
        self.item = item
        self.left = None
        self.right = None
class Tree():
    def __init__(self):
        self.root = None
    def insert(self,item):
        node = Node(item)
        cur = self.root
        if cur is None:
            self.root = node
            return
        while True:
            if item < cur.item:
                if cur.left is None:
                    cur.left = node
                    return
                else:
                    cur = cur.left
            else:
                if cur.right is None:
                    cur.right = node
                    return
                else:
                    cur = cur.right
    def preTravel(self,root):
        if root is None:
            return
        print(root.item,end= )
        self.preTravel(root.left)
        self.preTravel(root.right)
    def middleTravel(self,root):
        if root is None:
            return
        self.middleTravel(root.left)
        print(root.item,end= )
        self.middleTravel(root.right)
    def backTravel(self,root):
        if root is None:
            return
        self.backTravel(root.left)
        self.backTravel(root.right)
        print(root.item,end= )
        
tree = Tree()
tree.insert(3)
tree.insert(8)
tree.insert(5)
tree.insert(7)
tree.insert(6)
tree.preTravel(tree.root)
print(\n)
tree.middleTravel(tree.root)
print(\n)
tree.backTravel(tree.root)
print(\n)

            

 

以上是关于11.二叉树的主要内容,如果未能解决你的问题,请参考以下文章

二叉树练习题

NC41 最长无重复子数组/NC133链表的奇偶重排/NC116把数字翻译成字符串/NC135 股票交易的最大收益/NC126换钱的最少货币数/NC45实现二叉树先序,中序和后序遍历(递归)(代码片段

二叉树操作复习

算法 翻转二叉树 dfs

二叉树11:完全二叉树的节点个数

⭐算法入门⭐《二叉树 - 二叉搜索树》简单11 —— LeetCode 109. 有序链表转换二叉搜索树