第8章 二叉树

class Solution {
    public List<Integer> inorderTraversal(TreeNode root) {
        List<Integer> nodes = new LinkedList<>();
        Deque<TreeNode> stack = new LinkedList<TreeNode>();
        TreeNode cur = root;
        while(cur != null || !stack.isEmpty()){
            while(cur != null){
                stack.offer(cur);
                cur = cur.left;
            }
            cur = stack.pollLast();
            
            nodes.add(cur.val);//访问节点
            
            cur = cur.right;
        }
        return nodes;
    }
}