
7 Algorithms That Rule the World - bardonadam
https://www.youtube.com/watch?v=DsXtYx7RfqE
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bhouston
TL;DW summary from the video caption:

1\. Fast Fourier Transfrom

2\. Link Analysis

3\. Data Compression

4\. Dijkstra's Algorithm

5\. RSA Algorithm

6\. Proportional Integral Derivativ Algorithm

7\. Sorting Algorithms

I guess that makes sense. Skipping any AI or computer graphics algorithms or
optimization or database (paxos) or scaling/parallel algorithms.

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OskarS
Something I've wondered for a while: how many things actually use Dijkstra's
algorithm, in practice? I know how it works, and I've implemented shortest-
path graph algorithms a few times, but it's always been fairly easy to find at
least some kind of admissable heuristic, so why would you implement Dijkstra
over A-star? (edit: stupid hacker news markup wont let me escape the asterisk)

Obviously, when your graph has some sort of geometric interpretation (i.e. a
map or something), euclidian distance is the obvious choice (or Manhattan
distance if you're on a grid, etc.), but even for relatively abstract things
you might use graph search for you can usually figure out _something_. Like,
if you're trying to find the shortest solution to a sliding block puzzle using
a graph algorithm (where each node connects to all other nodes you can get to
in one move), you can use some sort heuristic based on the number of
inversions, or whatever. Even if your heuristic is kinda bad, it's almost
certainly better than no heuristic at all.

Dijkstra's algorithm has always seemed to me to be the "canonical academic
shortest-path algorithm that always works", but in reality everyone uses
A-star instead, because for all practical purposes it's way better, and not
much more complicated to implement.

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iAm25626
OSPF routing protocol(IGP) on network gear use Dijkstra. Most network within
mid/large enterprise use it. On a unrelated note it's fascinating to me that
the some obscure algorithm came way before actual technology implementation.
reminded me of [https://xkcd.com/435/](https://xkcd.com/435/) math ->
algorithm -> tech

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avmich
While FFT is pretty powerful and heavily used, I doubt you can't have Internet
without it.

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bardonadam
The whole networking is dependent on FFT.

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avmich
I don't think it's required. Can be used for many things in networking, yes,
but not required.

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bardonadam
EDIT: 100 subscribers! Thank you guys! :)

