抱歉，这里忘记改到...
正确的注解应该是：
// Move the BDD nodes in the cone [fromLevel, thisLevel] to toLevel.
// Return the resulted BDD node.
//
// [Note] If (fromLevel > toLevel) ==> move down
// If (fromLevel < toLevel) ==> move up
//
// [Note] If (move up), there is no node >= toLevel in the beginning.
// That is, toLevel > thisLevel.
// After the move, there will be no BDD nodes between
// [fromLevel, toLevel).
//
// [Note] If (move down),
// after the move, there will be no BDD node >= from Level
//
// In eithr case, before the move, need to make sure:
// 1. (thisLevel - fromLevel) < abs(fromLevel - toLevel)
// 2. There is no node < fromLevel (except for the terminal node).
// If any of the above is violated, isMoved will be set to false,
// no move will be made, and return (*this).
//
※ 引述《angelicdream (Angelic Dream)》之铭言：
: 在"Homework_4_2"中, page 11 关于nodeMove的叙述
: After the move,
: there will be no BDD nodes between levels [fromLevel, toLevel)
: 这叙述应该是错的...
: 以本题为例子,
: 比方说把Y搬到X,
: 所以fromLevel设成Y的lowest level,
: toLevel设成X之Lowest level
: 在[toLevel, fromLevel) 的区段都是X的node,不会发生"no BDD nodes."
: 建议本条说明要写清楚为一次搬动很多个level的node,
: 不然很容易理解错误,
: 像我刚刚以为是一次搬动一个level的node,
: 再加上叙述
: "There is no node in level < from Level (except for the terminal node)"
: 所以就要从Y最下层开始搬,
: 就写的拉哩拉杂..
: 两边加在一起,让我debug很久...
: 直到爬了一下文才解决问题@@
: 希望本篇能解决同样陷入这个问题的人的疑惑~~
: 若需爬文,最近与hw4-2相关的文章是295~298篇.