Past Meetup

Elijah Ben Izzy on Divide and Conquer Algorithms

This Meetup is past

167 people went

Two Sigma

101 Ave. of the Americas, 23rd Fl. J · New York

How to find us

Cross Streets: Watt and Grand. *Note:* Please make sure you’re signed-up for the meetup, including your first and last name. Without this info you won’t be allowed into the building by security.

Location image of event venue


**Please note the later start time! We will open doors at 7pm and begin at 7:30pm**

We are excited to host Elijah Ben Izzy speaking on Divide and Conquer Algorithms for Closest Point problems in Multidimensional Space (


Given n points in k dimensional space, how can you efficiently find the pair that is closest together? It turns out that there’s an elegant, divide-and-conquer approach that utilizes a nifty trick. Jon Luis Bentley, a pioneer in the space of geometric algorithms, proposes this solution (and answers many more problems) in his original PhD thesis, written in 1976. The talk will focus in on his solution to the closest-pair problem, then discuss some general approaches to algorithm construction that he outlined when defending his thesis... all written with a type-writer.

Elijah is a quantitative software engineer at Two Sigma. Ever since he started studying CS in college, he’s loved taking deep dives into complex, elegant algorithms and building out systems to support them. He came across Jon Luis Bentley’s PhD thesis when researching for an algorithms class, and found it to be a piece of archaeological computer science gold.


Lightning Talk:

Dan Rubenstein will present "Time, Clocks and the Ordering of Events in a Distributed System" by Leslie Lamport (

Today, we take the ability to look at our phone and see what time it is for granted. But what if time weren’t so easy? In his 1978 paper “Time, Clocks, and the Ordering of Events in a Distributed System”, Leslie Lamport illustrates several key facts with time and events in distributed systems that have key importance for our ‘web-scale’ systems of 2018. We’ll investigate a few concepts from the paper, and try to understand why clocks may not be so straightforward after all.

Dan Rubenstein is a software engineer at Blue State Digital. He’s worked on political campaigns in three electoral cycles, and is happy to hear your theory for why the polls were wrong.



**Doors open at 7:00 pm**; the presentations will begin right around 7:30 pm; and, yes, there will be refreshments of all kinds and pizza.

You'll have to check-in with security with your Name/ID. Definitely sign-up if you’re going to attend–unfortunately people whose names aren’t entered into the security system in advance won’t be allowed in.

After Elijah's presentation, we will open up the floor to discussion and questions.

We hope that you'll read some of the papers and references before the meetup, but don't stress if you can't. If you have any questions, thoughts, or related information, please visit #pwlnyc ( on slack (, our GitHub repository (, or add to the discussion on this event's thread.