94. 二叉树的中序遍历

中序递归/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode() {} * TreeNode(int val) { this.val val; } * TreeNode(int val, TreeNode left, TreeNode right) { * this.val val; * this.left left; * this.right right; * } * } */ class Solution { ListInteger list new ArrayList(); public ListInteger inorderTraversal(TreeNode root) { digui(root); return list; } public void digui(TreeNode root) { if (root null) return; digui(root.left); list.add(root.val); digui(root.right); } }