(RubyConf 2016) Computer Science: The Good Parts

My keynote talk from RubyConf 2016 in Cincinnati.

Transcript

1. Computer Science: The Good Parts Jeffrey Cohen
 @jeffcohen jeffcohenonline.com
3. Data Structures
4. Data Structures
5. Linked List
6. 60 31 5 45 80 70 74 99 87 68 Binary Tree
7. Data Structures
8. Graph
15. Algorithms
16. Babbage and Lovelace
17. Apollo 11
18. Margaret Hamilton Source code of the Apollo Guidance Computer
19. Complexity A "green" test suite is not an indicator of sustainability. Some implementations are more complex than others. • Time • Space
20. O(n) def exists?(name_to_find, names) names.each do |name| return true if name == name_to_find end return false end
21. def exists?(name_to_find, names) names.each do |name| return true if name == name_to_find end return false end O(n) 0 100 200 300 O(n)
22. O(log n) def exists?(name_to_find, sorted_names) 
 
 midpoint = sorted_names.length / 2 
 return true if sorted_names[midpoint].name == name_to_find 
 if name < sorted_names[midpoint].name 
 search(name_to_find, sorted_names[0, midpoint]) 
 else 
 search(name_to_find, sorted_names[midpoint, -1]) 
 end 
 return false
 end
23. def exists?(name_to_find, sorted_names) 
 
 midpoint = sorted_names.length / 2 
 return true if sorted_names[midpoint].name == name_to_find 
 if name < sorted_names[midpoint].name 
 search(name_to_find, sorted_names[0, midpoint]) 
 else 
 search(name_to_find, sorted_names[midpoint, -1]) 
 end 
 return false
 end O(log n) 0 100 200 300 O(log n) O(n)
24. Atom.io blog post
25. O(n2) def make_combinations(items) items.map do |item| items.map { |inner_item| [item, inner_item] } end end [1,2,3] => [[1,1], [1,2], [1,3], [2, 1], [2, 2], [2, 3], [3, 1], [3, 2], [3, 3]]
26. O(n2) def make_combinations(items) items.map do |item| items.map { |inner_item| [item, inner_item] } end end 0 100 200 300 O(n2) O(n) O(log n)
27. The Future
28. Alan Turing
29. Alan Turing Computer science
 is not
 computer programming
30. Alan Turing It's a way of thinking
31. Grace Hopper
32. Grace Hopper
33. Grace Hopper Humans are allergic to change. They love to say, "We've always done it this way." I try to fight that.
 
 That's why I have a clock on my wall that runs counter-clockwise.
34. Grace Hopper A ship in port is safe; but that is not what ships are built for. Sail out to sea and do new things.
35. Questions? Thoughts? Find me on twitter
 @jeffcohen
 
 
 jeffcohenonline.com