[Clyde Schechter]

That code was written a while ago, and it's fairly lengthy and does a bunch of things. So rather than trying to adapt it to your situation, I think you are better off with some very simple code starting from scratch:

* Example generated by -dataex-. To install: ssc install dataex
clear
input long id double(noi_start noi_end)
1 12 26
1 32 36
2  5 20
3  7 15
4  9 20
4 30 40
4 40 45
5  3  6
5 10 15
6  2 36
7 17 19
8 15 24
end

by id (noi_start), sort: gen spell = sum(_n == 1 | noi_start > noi_end[_n-1])
collapse (min) noi_start (max) noi_end, by(id spell)