[LeetCode]题解（python）：094 Binary Tree Inorder Traversal

题目来源

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https://leetcode.com/problems/binary-tree-inorder-traversal/

iven 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].

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题意分析

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Input:tree

Output: inorder traversal

Conditions:中序遍历，要非递归

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题目思路

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非递归实现

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AC代码（Python）

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

class Solution:
    # @param root, a tree node
    # @return a list of integers
    def iterative_inorder(self, root, list):
        stack = []
        while root or stack:
            if root:
                stack.append(root)
                root = root.left
            else:
                root = stack.pop()
                list.append(root.val)
                root = root.right
        return list
                
    def recursive_inorder(self, root, list):
        if root:
            self.inorder(root.left, list)
            list.append(root.val)
            self.inorder(root.right, list)
        
    def inorderTraversal(self, root):
        list = []
        self.iterative_inorder(root, list)
        return list