94. 二叉树的中序遍历
webVueBlog opened this issue · comments
94. 二叉树的中序遍历
Description
Difficulty: 简单
Related Topics: 栈, 树, 深度优先搜索, 二叉树
给定一个二叉树的根节点 root
,返回 它的 中序 遍历 。
示例 1:
输入:root = [1,null,2,3]
输出:[1,3,2]
示例 2:
输入:root = []
输出:[]
示例 3:
输入:root = [1]
输出:[1]
提示:
- 树中节点数目在范围
[0, 100]
内 -100 <= Node.val <= 100
进阶: 递归算法很简单,你可以通过迭代算法完成吗?
Solution
Language: JavaScript
/**
* Definition for a binary tree node.
* function TreeNode(val, left, right) {
* this.val = (val===undefined ? 0 : val)
* this.left = (left===undefined ? null : left)
* this.right = (right===undefined ? null : right)
* }
*/
/**
* @param {TreeNode} root
* @return {number[]}
*/
// 栈
var inorderTraversal = function(root) {
const res = []
let stack = []
while (root || stack.length) {
while (root) {
stack.push(root)
root = root.left
}
root = stack.pop()
res.push(root.val)
root = root.right
}
return res
}