Tree traversal
The former sequence traversal
In the sequence traversal
private List<Integer> ans; public List<Integer> inorderTraversal(TreeNode root) { ans = new ArrayList<>(); inorders(root); return ans; } private void inorders(TreeNode root) { if (root == null) { return; } inorders(root.left); ans.add(root.val); inorders(root.right); } public static void main(String[] args) { TreeNode node1 = new TreeNode(1); TreeNode node2 = new TreeNode(2); TreeNode node3 = new TreeNode(3); node1.right = node2; node2.left = node3; InorderTraversal94 inorderTraversal94 = new InorderTraversal94(); List<Integer> result = inorderTraversal94.inorderTraversal(node1); Println (" result:{}" + result.toString()); }Copy the code