我不了解代码中的“继续”。 leetcode问题

Question

我不理解代码中的“继续”。 预期的输出：[1,2,3] 当我删除“ continue”时，输出：[1,2]; ... 这是leetcode的问题

https://leetcode.com/problems/binary-tree-preorder-traversal/

class Solution {
    public List<Integer> preorderTraversal(TreeNode root) {
        List<Integer> res = new ArrayList<>();
        helpByMorris(root, res);
        return res;
    }
    private void helpByMorris(TreeNode root, List<Integer> res){
        if(root == null) return;
        TreeNode cur = root;
        TreeNode mostRight = null;

        while(cur != null){
            mostRight = cur.left;
            if(mostRight != null){
                while(mostRight.right != null && mostRight.right != cur){
                    mostRight = mostRight.right;
                }
                if(mostRight.right == null){
                    mostRight.right = cur;
                    res.add(cur.val);
                    cur = cur.left;
                    continue; // here is my confusion
                }else{
                    mostRight.right = null;
                }
            }else{ 
                res.add(cur.val);
            }
            cur = cur.right;
        }
    }

}