Algorithms and Their Habitat

Algorithms are mysterious beasts that hard to catch in the source code. However, well-chosen data structures and efficient algorithms applied to a web app is key to performance. I want to show how to fit the knowledge you got at the university can solve your daily routines.

Transcript

1. Algorithms and Their Habitat
2. Vitalii Bobrov Lead JS Engineer @AngularWroclaw organizer ngGirls mentor @bobrov1989 https://bobrov.dev
3. Algorithms
4. unambiguous specification of how to solve a class of problems
5. Why should I care?!
6. They are EVERYWHERE
7. Maintain your library to find the way
8. Complexity
9. understand how application will scale
10. Big O
13. TIME and SPACE Complexity estimate resources highlight bottlenecks force to find better solution
14. Data Normalization
15. WHEN? related state entities recursive state entities fast entity lookup
16. Data with Relations
17. Recursive Data
18. WHY? get entity by id get entities by related id reduce memory footprint
19. Data with relations - get entity O(n) O(n*m)
20. Recursive data - get entity memory O(n) time O(n)
22. Normalized data
23. Normalized data - get entity O(1) O(1) O(n*m)
24. prepare index to get entities faster
25. Normalized data - index
26. Normalized data - get entity O(n)
27. HOW? do it yourself use library normalizr @ngrx/entity https://github.com/paularmstrong/normalizr https://ngrx.io/guide/entity
28. Memoization
29. WHEN? data selection repeated computations derived data
30. Fibonacci numbers
31. Call tree
32. WHY? reduce expensive calls frequently used data reduce callstack
33. Memoized
34. HOW? do it yourself use library reselect mem https://github.com/reduxjs/reselect https://github.com/sindresorhus/mem
35. Levenshtein Distance
36. calculates how many edits required to get one string from another
37. Distance matrix
39. WHEN? auto-correction auto-completion smart suggestions
42. use Levenshtein distance for smart 404 page
43. HOW? https://bobrov.dev/blog/angular-smart-404-page/ https://bobrov.dev/ngx-smart-routing-demo/ get the list of available routes sort routes by Levenshtein
 distance to a user input suggest route with the smallest distance
44. Get all available routes
45. Sort by Levenshtein distance
46. Suggest route
48. Create non-standard use-case
49. @bobrov1989 https://bobrov.dev