Method bfs

java/0199-binary-tree-right-side-view.java:10–22

(List<Integer> list, TreeNode root)

    }

    public void bfs(List<Integer> list, TreeNode root) {
        Queue<TreeNode> q = new LinkedList<>();
        q.offer(root);
        while (!q.isEmpty()) {
            int levelSize = q.size();
            for (int i = 0; i < levelSize; i++) {
                TreeNode cur = q.poll();
                if (i == 0) list.add(cur.val);
                if (cur.right != null) q.offer(cur.right);
                if (cur.left != null) q.offer(cur.left);
            }
        }
    }
}