今日の"どう書く"問題のアルゴリズム例

Nagoya.php #15 補足資料
https://nagoyaphp.connpass.com/event/120856/

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
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