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| public class BinaryTreeInorderTraversal {
public List<Integer> inorderTraversal(TreeNode root) {
List<Integer> result = new ArrayList<Integer>();
if (root == null) {
return result;
}
helper(root, result);
return result;
}
private void helper(TreeNode root, List<Integer> result) {
if (root != null && root.left == null && root.right == null) {
result.add(root.val);
} else {
if (root.left != null) {
helper(root.left, result);
}
result.add(root.val);
if (root.right != null) {
helper(root.right, result);
}
}
}
}
|