线索化二叉排序树操作：具有线索化节点结构的二叉排序树。基于学生分数统计的应用背景，包含线索化后排序树的插入、删除、遍历等基本操作。-Threaded binary sort tree steps: have a clue of the node structure binary sort tree. Score based on student application of statistical background, contains clues to sort the tree after