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# sweep line & interval

career event:

用（end, duration)排序，Greedy做法，好多容纳更多event.

代表2段interval有交集。

```
if (Math.max(b[0], start) < Math.min(b[1], end)) return false;
```

meeting room I II

the skyline problem

merge interval

注意先降后升所以降-1<升+1

interval排序时候，sort默认先按a\[0]再按a\[1]（就是都排了）

如果只按start排序，注意要用key

**merge interval** 需要按start sort， end排不排无所谓

**meeting room**需要都排，所以才需要拆成times，先降后升