/**
 * 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 {
    private void traverse(TreeNode root, List<Integer> list) {
        if (root == null) {
            return;
        }

        if (root.left == null && root.right == null) {
            list.add(root.val);
            return;
        }

        traverse(root.left, list);
        traverse(root.right, list);
    }
    public boolean leafSimilar(TreeNode root1, TreeNode root2) {
        List<Integer> list1 = new LinkedList<Integer>();
        List<Integer> list2 = new LinkedList<Integer>();
        traverse(root1, list1);
        traverse(root2, list2);

        System.out.println(list1);
        System.out.println(list2);
        if (list1.size() != list2.size()) {
            return false;
        }

        for (int i = 0; i < list1.size(); i++) {
            // Note: in Java you should not use == when you compare objects of
            // a class that wraps a primitive type. You would be comparing a
            // reference instead of the actual value.
            if (!list1.get(i).equals(list2.get(i))) {
                return false;
            }
        }

        return true;
    }
}


// iterative approach
// class Solution {
//     private void traverse(TreeNode root, List<Integer> list) {
//         Stack<TreeNode> stack = new Stack<TreeNode>();
//         stack.push(root);
//         while (!stack.isEmpty()) {
//             TreeNode curr = stack.pop();

//             if (curr.left == null && curr.right == null) {
//                 list.add(curr.val);
//             }
//             if (curr.left != null) {
//                 stack.push(curr.left);
//             }
//             if (curr.right != null) {
//                 stack.push(curr.right);
//             }
//         }
//     }
//     public boolean leafSimilar(TreeNode root1, TreeNode root2) {
//         List<Integer> list1 = new LinkedList<Integer>();
//         List<Integer> list2 = new LinkedList<Integer>();
//         traverse(root1, list1);
//         traverse(root2, list2);

//         System.out.println(list1);
//         System.out.println(list2);
//         if (list1.size() != list2.size()) {
//             return false;
//         }

//         for (int i = 0; i < list1.size(); i++) {
//             if (list1.get(i).intValue() != list2.get(i).intValue()) {
//                 return false;
//             }
//         }

//         return true;
//     }
// }