[leetcode] Binary Tree Inorder Traversal

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/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ public class Solution { public List<Integer> inorderTraversal(TreeNode root) { List<Integer> result = new ArrayList<Integer>(); if (root == null){ return result; } Stack<TreeNode> stack = new Stack<TreeNode>(); stack.add(root); root = root.left; while(!stack.isEmpty()){ if (root == null){ TreeNode temp = stack.pop(); result.add(temp.val); root = temp.right; } if (root != null){ stack.push(root); root = root.left; } } return result; } }