- 1. process的时候，画个图也可以搞清楚: 就是四个方向都走走，用curr cell的高度减去周围cell的高度. - 2. 若大于零，那么周围的cell就有积水: 因为cell已经是外围最低, 所以内部更低的, 一定有积水. - 3. 每个visited的cell都要mark, avoid revisit - 4. 根据4个方向的走位 `(mX ...

There are n different online courses numbered from 1 to n. Each course has some duration (course length) t and closed on dth day. A course should be taken continuously for t days and must be finished ...