[LeetCode] Binary Tree Inorder Traversal

最新推荐文章于 2020-07-28 10:43:41 发布

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最新推荐文章于 2020-07-28 10:43:41 发布

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原文链接：http://www.cnblogs.com/vincently/p/4229674.html

本文介绍了一种不使用递归的方法来完成二叉树节点值的中序遍历。通过栈结构实现对二叉树节点的访问顺序控制，确保了输出结果符合中序遍历的要求。

Given a binary tree, return the inorder traversal of its nodes' values.

For example:
Given binary tree {1,#,2,3},

return [1,3,2].

Note: Recursive solution is trivial, could you do it iteratively?

 1 /**
 2  * Definition for binary tree
 3  * struct TreeNode {
 4  *     int val;
 5  *     TreeNode *left;
 6  *     TreeNode *right;
 7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 8  * };
 9  */
10 class Solution {
11 public:
12     vector<int> inorderTraversal(TreeNode *root) {
13         vector<int> result;
14         stack<TreeNode *> s;
15         TreeNode *p = root;
16         
17         while (p != nullptr || !s.empty()) {
18             if (p != nullptr) {
19                 s.push(p);
20                 p = p->left;
21             } else {
22                 p = s.top();
23                 s.pop();
24                 result.push_back(p->val);
25                 p = p->right;
26             }
27         }
28         
29         return result;
30      }
31 };

转载于:https://www.cnblogs.com/vincently/p/4229674.html