LeetCode Binary Tree Inorder Traversal

LeetCode解题之Binary Tree Inorder Traversal


原题

不用递归来实现树的中序遍历。

注意点:

例子:

输入: {1,#,2,3}

   1
         2
    /
   3

输出: [1,3,2]

解题思路

通过栈来实现,从根节点开始,不断寻找左节点,并把这些节点依次压入栈内,只有在该节点没有左节点或者它的左子树都已经遍历完成后,它才会从栈内弹出,这时候访问该节点,并它的右节点当做新的根节点一样不断遍历。

AC源码

# Definition for a binary tree node.
class TreeNode(object):
    def __init__(self, x):
        self.val = x
        self.left = None
        self.right = None

class Solution(object):
    def inorderTraversal(self, root):
        """
        :type root: TreeNode
        :rtype: List[int]
        """
        result = []
        stack = []
        p = root
        while p or stack:
            # Save the nodes which have left child
            while p:
                stack.append(p)
                p = p.left
            if stack:
                p = stack.pop()
                # Visit the middle node
                result.append(p.val)
                # Visit the right subtree
                p = p.right
        return result

if __name__ == "__main__":
    n1 = TreeNode(1)
    n2 = TreeNode(2)
    n3 = TreeNode(3)
    n1.right = n2
    n2.left = n3
    assert Solution().inorderTraversal(n1) == [1, 3, 2]

欢迎查看我的Github (https://github.com/gavinfish/LeetCode-Python) 来获得相关源码。

时间: 2024-10-10 12:32:28

LeetCode Binary Tree Inorder Traversal的相关文章

LeetCode: Binary Tree Inorder Traversal [094]

[题目] Given a binary tree, return the inorder traversal of its nodes' values. For example: Given binary tree {1,#,2,3}, 1 2 / 3 return [1,3,2]. Note: Recursive solution is trivial, could you do it iteratively? confused what "{1,#,2,3}" means? >

[leetcode]Binary Tree Inorder Traversal @ Python

原题地址:http://oj.leetcode.com/problems/binary-tree-inorder-traversal/ 题意:二叉树的中序遍历. 解题思路:这道题用递归解不难,所以应该考察的是非递归求解二叉树的中序遍历.我们使用一个栈来解决问题.比如一颗二叉树为{1,2,3,4,5,6,7},第一层为{1},第二层为{2,3},第三层为{4,5,6,7}.那么我们依次存储左子树的根节点,那么入栈顺序为:1,2,4.由于4的左子树为空,所以开始出栈.4出栈,检查4的右子树为空,继续

LeetCode——Binary Tree Inorder Traversal

Given a binary tree, return the inorder traversal of its nodes' values. For example: Given binary tree {1,#,2,3}, 1 2 / 3 return [1,3,2]. Note: Recursive solution is trivial, could you do it iteratively? 原题链接:https://oj.leetcode.com/problems/binary-t

Leetcode: Binary Tree Inorder Traversal(二叉树中序遍历)

题目: Given a binary tree, return the inorder traversal of its nodes' values. For example: Given binary tree {1,#,2,3}, 1 2 / 3 return [1,3,2]. Note: Recursive solution is trivial, could you do it iteratively? 递归解法(C++): /** * Definition for binary tre

LeetCode: Binary Tree Inorder Traversal 解题报告

Binary Tree Inorder Traversal Given a binary tree, return the inorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3},   1    \     2    /   3return [1,3,2]. Note: Recursive solution is trivial, could you do it iteratively? co

[LeetCode] Binary Tree Inorder Traversal 中序排序

Given a binary tree, return the inorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3}, 1 2 / 3 return [1,3,2]. Note: Recursive solution is trivial, could you do it iteratively? confused what "{1,#,2,3}" means? > read

[LeetCode] Binary Tree Inorder Traversal 二叉树的中序遍历

Given a binary tree, return the inorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3}, 1 2 / 3 return [1,3,2]. Note: Recursive solution is trivial, could you do it iteratively? confused what "{1,#,2,3}" means? > read

leetcode -day29 Binary Tree Inorder Traversal & Restore IP Addresses

1.  Binary Tree Inorder Traversal Given a binary tree, return the inorder traversal of its nodes' values. For example: Given binary tree {1,#,2,3}, 1 2 / 3 return [1,3,2]. Note: Recursive solution is trivial, could you do it iteratively? 分析:求二叉树的中序

[LeetCode][JavaScript]Binary Tree Inorder Traversal

Binary Tree Inorder Traversal Given a binary tree, return the inorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3}, 1 2 / 3 return [1,3,2]. Note: Recursive solution is trivial, could you do it iteratively? https://leetcode.