The LCA problem revisited [pdf](www3.cs.stonybrook.edu)
www3.cs.stonybrook.edu
The LCA problem revisited [pdf]
https://www3.cs.stonybrook.edu/~bender/talks/BenderFa00-lca-talk.pdf
9 comments
The range minimum query problem (RMQ) used to solve LCA is a really fun one. I spend two lectures on it in my advanced data structures course. The approach covered in the slides linked here is perhaps the best-known way to solve LCA via RMQ, but I personally prefer one developed by Fischer and Heun in 2006. Check the first two lectures of my course (https://web.stanford.edu/class/archive/cs/cs166/cs166.1256/) for details.
Thanks a lot for the wonderful slides, I used them to learn suffix arrays!
Range minimum query? Isn't that just prefix sum and a queue?
You are probably confusing it with a sliding window problem. RMQ [0] is about finding the minimum value in given arbitrary subarray.
[0] https://en.wikipedia.org/wiki/Range_minimum_query
[0] https://en.wikipedia.org/wiki/Range_minimum_query
You are right! That's interesting!
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Spoiler alert: there is at least one typo in the slides.
A preprint of the paper is available here: https://web.archive.org/web/20250708141740/https://www.ics.u...
A preprint of the paper is available here: https://web.archive.org/web/20250708141740/https://www.ics.u...
Maybe the takeaway is that I was born to be a programmer, and this was my fifth grade version of the old joke where the programmer's wife asks him to "get a gallon of milk, and if they have eggs, get a dozen."