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 a 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 @ EPAM @AngularWroclaw organizer experimenter @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. Complexity
8. understand how application will scale
9. Big O
12. TIME and SPACE Complexity estimate resources highlight bottlenecks force to find better solution
13. Data Normalization
14. WHEN? related state entities recursive state entities fast entity lookup
15. Data with Relations
16. Recursive Data
17. WHY? get entity by id get entities by related id reduce memory footprint
18. Data with relations - get entity O(n) O(n*m)
19. Recursive data - get entity memory O(n) time O(n)
21. Normalized data
22. Normalized data - get entity O(1) O(1) O(n*m)
23. prepare index to get entities faster
24. Normalized data - index
25. Normalized data - get entity O(n)
26. HOW? do it yourself use library normalizr @ngrx/entity https://github.com/paularmstrong/normalizr https://ngrx.io/guide/entity
27. Memoization
28. WHEN? data selection repeated computations derived data
29. Fibonacci numbers
30. Call tree
31. WHY? reduce expensive calls frequently used data reduce callstack
32. Memoized
33. HOW? do it yourself use library reselect mem https://github.com/reduxjs/reselect https://github.com/sindresorhus/mem
34. Levenshtein Distance
35. calculates how many edits required to get one string from another
36. Distance matrix
38. WHEN? auto-correction auto-completion smart suggestions
41. use Levenshtein distance for smart 404 page
42. “Helpful” UI
43. https://ngx-smart-routing-demo.web.app
44. HOW? https://bobrov.dev/blog/angular-smart-404-page/ https://ngx-smart-routing-demo.web.app get the list of available routes sort routes by Levenshtein
 distance to a user input suggest route with the smallest distance
45. Get all available routes
46. Sort by Levenshtein distance
47. Suggest route
48. Create non-standard use-case
49. @bobrov1989 https://bobrov.dev