算法考了一题，类似下面
只不过 plane 改成 thread了
Number of Airplanes in the Sky
Given an interval list which are flying and landing time of the flight. How many airplanes are on the sky at most?
Example
For interval list [[1,10],[2,3],[5,8],[4,7]], return 3
BQ问了简历，另外问了
- a time you try to take a problem outside your area or responsibility
- quick decision and quickly go through facts to make decision