今日の"どう書く"問題のアルゴリズム例

Transcript

1. ࠓ೔ͷ”Ͳ͏ॻ͘”໰୊ͷ ΞϧΰϦζϜྫ 2019/04/17 #nagoyaphp @ttskch

2. ๻ʹ͍ͭͯ

3. ͖ͨͭͪʢ໊͋ͩʣ • (ג)ΧϧςοτίϛϡχέʔγϣϯζCTO • WebΤϯδχΞྺ7೥ɺPHPྺ7೥ • #nagoyaphpʊ • #symfony_meetup

4. ͖ͨͭͪʢ໊͋ͩʣ • ͓ख఻͍ͨ͠ຊʢ2015/12ʣ • Schooߨࢣʢ2018/04ʣ ʮGitHubΛ࢖ͬͨσϓϩΠࣗಈԽ࣮ફʯ ʮجຊ͔Β͔ͬ͠ΓֶͿ Symfony2ೖ໳ʯ

5. ͨ ͭ ͖ ͪ twitter.com/ttskch ͋͞ɺ͋ͳͨ΋ࠓ͙͢ϑΥϩʔ͠Α͏!!! ׬શແྉ ·͞ʹ໊ݴ੡଄ػ ਓੜͰେ੾ͳ͜ͱ͸ɺ͢΂ͯ ͖͔ͨͭͪΒڭΘͬͨ

   ͖ͨͭͪΛϑΥϩʔͨ͠Β
 ࠊ௧͕࣏Γ·ͨ͠ 100% φϯτʂ ϑΥϩϫʔ͔Βͷࢧ࣋཰ 100% ͍ͯ͠Δ ͍ͯ͠ͳ͍ ϑΥϩϫʔ͞Μ100ਓʹฉ͖·ͨ͠ ͖ͨͭͪΛϑΥϩʔ͍ͯ͠Δʁ

6. ձࣾʹ͍ͭͯ

7. (ג)Χϧςοτίϛϡχέʔγϣϯζ https://quartet-communications.com

8. (ג)Χϧςοτίϛϡχέʔγϣϯζ https://www.google.co.jp/search?q=Χʔςϯ

9. (ג)Χϧςοτίϛϡχέʔγϣϯζ https://lisket.jp

10. We are hiring!ʢϚδͰʣ • PHPer/JSer ઈࢍେืूதʂʢϦϞʔτ΍όΠτ΋Մʣ • Symfony+Angular ͰɺWeb޿ࠂۀքΛ
 ϗϫΠτʹ͢Δ࢓૊ΈΛ࡞ͬͯ·͢

    • ܦӦϏδϣϯ͸ʮੈքҰޮ཰తͳ୅ཧళʯ

11. We are hiring!ʢϚδͰʣ • ࣗࣾαʔϏεʮLisketʯͰࣗࣾͷۀ຿΋ޮ཰Խ • શࣾһͷฏۉ࢒ۀ͕࣌ؒ5h/݄͙Β͍Ͱ͢ ಛผ৆ड৆

12. We are hiring!ʢϚδͰʣ ΤϯδχΞͷಇ͖΍͢͞௒େࣄʹͯ͠·͢✨

13. We are hiring!ʢϚδͰʣ ·ͣ͸͓࿩͚ͩͰ΋ʂؾܰʹ੠͔͚͍ͯͩ͘͞

14. ࠓ೔ͷ”Ͳ͏ॻ͘”໰୊ͷ ΞϧΰϦζϜྫ 2019/04/17 #nagoyaphp @ttskch

15. http://nabetani.sakura.ne.jp/hena/ordf04octsp/

16. ௖఺਺ͷٻΊํ

17. 1 2 4 8 16 32 64 128

18. 3 5 4 4

19. 3 5 4 4 1 2 3 2

20. 1 2 3 2 3 5 4 4 ؔ܎ͯͦ͠͏

21. 3 5 4 4 1 2 3 2

22. 3 5 4 4 1 2 3 2 3 -1

    = 2

23. 3 5 4 4 1 2 3 2 2 +

    3 = 5 3 -1 = 2

24. 3 5 4 4 1 2 3 2

25. 3 5 4 4 1 2 3 2 2 -1

    = 1

26. 3 5 4 4 1 2 3 2 1 +

    3 = 4 2 -1 = 1

27. 3 5 4 4 ࣮ઢؒͷڑ཭͔Β௖఺਺͸ٻΊΒΕΔ

28. 5

29. 5 4

30. 5 4 4 -1 = 3

31. 5 4 3 + 3 = 6 4 -1 =

    3

32. 5 4 4 -1 = 3 3 + 3 =

    6 3 + 2= 5

33. 5 4 ڑ཭͕4ͷͱ͖͚ͩܭࢉํ๏͕มΘΔ

34. 1 2 4 8 16 32 64 128

35. 2 8 16 64 1 2 3 2 1 4

    32 128

36. 21 23 24 26 1 2 3 2 20 22

    25 27

37. 21 23 24 26 1 2 3 2 20 22

    25 27

38. 21 23 24 26 1 2 3 2 20 22

    25 27 ൪߸Λ2ͷྦྷ৐Ͱද͢ͱࢦ਺෦ͷࠩͰڑ཭ΛٻΊΒΕΔ

39. 21 23 24 26 2 3 2 22 25 Ұप͢Δͱۙͮ͘ߏ଄ͳͷͰ8ͷ৒༨Λ࢖͑͹Αͦ͞͏✋

    1 20 27

40. ೖྗͷύʔε

41. 1 2 4 8 16 32 64 128

42. 2 8 16 64 165 Λ 1 + 4 +

    32 + 128 ʹ෼ղ͍ͨ͠ 1 4 32 128

43. 2 8 16 64 1 4 32 128

44. 21 23 24 26 20 22 25 27

45. 165 = 27x1 + 26x0 + 25x1 + 24x0 +

    23x0 + 22x1 + 21x0 + 20x1 21 23 24 26 20 22 25 27

46. 165 = b10100101 21 23 24 26 20 22 25

    27

47. 21 23 24 26 20 22 25 27 ೖྗΛ2ਐ਺Ͱද͢ͱɺ஋͕1ͷܻ͕࣮ઢͷҐஔΛࣔ͢

48. ࣮૷ྫ

49. public function run(string $input): string { $lines = array_values(array_filter(range(0, 7),

    function (int $i) use ($input) { return str_split(sprintf('%b', $input))[$i] ?? false; })); $vertices = []; for ($i = 0; $i < count($lines); $i++) { $distance = ($lines[($i + 1) % count($lines)] - $lines[$i] + 8) % 8; $vertices[] = ($distance === 4 ? 2 : 3) + $distance - 1; } sort($vertices); return implode('', $vertices); }

50. public function run(string $input): string { $lines = array_values(array_filter(range(0, 7),

    function (int $i) use ($input) { return str_split(sprintf('%b', $input))[$i] ?? false; })); $vertices = []; for ($i = 0; $i < count($lines); $i++) { $distance = ($lines[($i + 1) % count($lines)] - $lines[$i] + 8) % 8; $vertices[] = ($distance === 4 ? 2 : 3) + $distance - 1; } sort($vertices); return implode('', $vertices); } ೖྗΛ2ਐ਺ʹม׵ͯ͠ɺཱ͍ͬͯΔϏοτͷҐஔʢ0ʙ7ʣΛ഑ྻʹ͢Δɻ ྫ୊ͷ৔߹͸ $lines === [0, 2, 5, 7] ͱͳΔɻ͜Ε͕࣮ઢͷҐஔɻ ೖྗͷύʔε

51. public function run(string $input): string { $lines = array_values(array_filter(range(0, 7),

    function (int $i) use ($input) { return str_split(sprintf('%b', $input))[$i] ?? false; })); $vertices = []; for ($i = 0; $i < count($lines); $i++) { $distance = ($lines[($i + 1) % count($lines)] - $lines[$i] + 8) % 8; $vertices[] = ($distance === 4 ? 2 : 3) + $distance - 1; } sort($vertices); return implode('', $vertices); } [0, 2, 5, 7] ͱ͍͏഑ྻʹରͯ͠ɺཁૉؒͷ͔ࠩΒ࣮ઢؒͷڑ཭ΛٻΊΔͱɺ (2-0+8)%8=2, (5-2+8)%8=3, (7-5+8)%8=2, (0-7+8)%8=1 ͱͳΔɻ ڑ཭͕4ͷ৔߹͸ 2+ڑ཭-1 ͕ɺڑ཭͕ͦΕҎ֎ͷ৔߹͸ 3+ڑ཭-1 ͕௖఺਺ɻ ௖఺਺ͷܭࢉ

52. https://github.com/ ttskch/nagoyaphp15

53. @ttskch ʘThanks!ʗ