Add milk2.cpp. Sacrifice memory for easiness. Use bool map[1000000+1] to indicate which interval is occupied. Then scan it to get the longest occupied and non-occupied intervals.
Add milk2_merge_interval.cpp. Like Merge Intervals on leetcode.com. Input all intervals first, then sort. Then merge the intervals one by one. If we can't merge, update maxOcuSpan, maxNonOcuSpan.
Add !!! in milk2_merge_interval.cpp 2) Add template.cpp
Add a problematic transform.cpp