Ask HN: What is the best concept in CS/Math you've ever learnt and why?
Where can we read about that concept? A link to a blog, paper, etc would be helpful.
Why do you think that particular concept is the best?
Why do you think that particular concept is the best?
If you've got a queue of any form, you can throw Little's Law at it.
"the long-term average number L of customers in a stationary system is equal to the long-term average effective arrival rate λ multiplied by the average time W that a customer spends in the system. Expressed algebraically the law is L = λW"
[1] https://en.wikipedia.org/wiki/Little%27s_law
I frequently bring up the Secretary problem when talking to people about dating and job hunting:
(1) estimate the size of your candidate pool as N, (2) reject sqrt(N) candidates, (3) choose the first candidate that is better than all others.
Street Fighting Mathematics by Sanjoy Mahajan.