(RubyConf 2016) Computer Science: The Good Parts

Transcript

1. Computer Science: The Good Parts Jeffrey Cohen
 @jeffcohen jeffcohenonline.com

2. None

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

9. None
10. None
11. None
12. None
13. None
14. None

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