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今日の"どう書く"問題のアルゴリズム例
Takashi Kanemoto
April 17, 2019
Programming
1
140
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/
Takashi Kanemoto
April 17, 2019
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Transcript
ࠓͷ”Ͳ͏ॻ͘”ͷ ΞϧΰϦζϜྫ 2019/04/17 #nagoyaphp @ttskch
ʹ͍ͭͯ
͖ͨͭͪʢ໊͋ͩʣ • (ג)ΧϧςοτίϛϡχέʔγϣϯζCTO • WebΤϯδχΞྺ7ɺPHPྺ7 • #nagoyaphpʊ • #symfony_meetup
͖ͨͭͪʢ໊͋ͩʣ • ͓ख͍ͨ͠ຊʢ2015/12ʣ • Schooߨࢣʢ2018/04ʣ ʮGitHubΛͬͨσϓϩΠࣗಈԽ࣮ફʯ ʮجຊ͔Β͔ͬ͠ΓֶͿ Symfony2ೖʯ
ͨ ͭ ͖ ͪ twitter.com/ttskch ͋͞ɺ͋ͳͨࠓ͙͢ϑΥϩʔ͠Α͏!!! શແྉ ·͞ʹ໊ݴػ ਓੜͰେͳ͜ͱɺͯ͢ ͖͔ͨͭͪΒڭΘͬͨ
͖ͨͭͪΛϑΥϩʔͨ͠Β ࠊ௧͕࣏Γ·ͨ͠ 100% φϯτʂ ϑΥϩϫʔ͔Βͷࢧ࣋ 100% ͍ͯ͠Δ ͍ͯ͠ͳ͍ ϑΥϩϫʔ͞Μ100ਓʹฉ͖·ͨ͠ ͖ͨͭͪΛϑΥϩʔ͍ͯ͠Δʁ
ձࣾʹ͍ͭͯ
(ג)Χϧςοτίϛϡχέʔγϣϯζ https://quartet-communications.com
(ג)Χϧςοτίϛϡχέʔγϣϯζ https://www.google.co.jp/search?q=Χʔςϯ
(ג)Χϧςοτίϛϡχέʔγϣϯζ https://lisket.jp
We are hiring!ʢϚδͰʣ • PHPer/JSer ઈࢍେืूதʂʢϦϞʔτόΠτՄʣ • Symfony+Angular ͰɺWebࠂۀքΛ ϗϫΠτʹ͢ΔΈΛ࡞ͬͯ·͢
• ܦӦϏδϣϯʮੈքҰޮతͳཧళʯ
We are hiring!ʢϚδͰʣ • ࣗࣾαʔϏεʮLisketʯͰࣗࣾͷۀޮԽ • શࣾһͷฏۉۀ͕࣌ؒ5h/݄͙Β͍Ͱ͢ ಛผड
We are hiring!ʢϚδͰʣ ΤϯδχΞͷಇ͖͢͞େࣄʹͯ͠·͢✨
We are hiring!ʢϚδͰʣ ·͓͚ͣͩͰʂؾܰʹ͔͚͍ͯͩ͘͞
ࠓͷ”Ͳ͏ॻ͘”ͷ ΞϧΰϦζϜྫ 2019/04/17 #nagoyaphp @ttskch
http://nabetani.sakura.ne.jp/hena/ordf04octsp/
ͷٻΊํ
1 2 4 8 16 32 64 128
3 5 4 4
3 5 4 4 1 2 3 2
1 2 3 2 3 5 4 4 ؔͯͦ͠͏
3 5 4 4 1 2 3 2
3 5 4 4 1 2 3 2 3 -1
= 2
3 5 4 4 1 2 3 2 2 +
3 = 5 3 -1 = 2
3 5 4 4 1 2 3 2
3 5 4 4 1 2 3 2 2 -1
= 1
3 5 4 4 1 2 3 2 1 +
3 = 4 2 -1 = 1
3 5 4 4 ࣮ઢؒͷڑ͔ΒٻΊΒΕΔ
5
5 4
5 4 4 -1 = 3
5 4 3 + 3 = 6 4 -1 =
3
5 4 4 -1 = 3 3 + 3 =
6 3 + 2= 5
5 4 ڑ͕4ͷͱ͖͚ͩܭࢉํ๏͕มΘΔ
1 2 4 8 16 32 64 128
2 8 16 64 1 2 3 2 1 4
32 128
21 23 24 26 1 2 3 2 20 22
25 27
21 23 24 26 1 2 3 2 20 22
25 27
21 23 24 26 1 2 3 2 20 22
25 27 ൪߸Λ2ͷྦྷͰද͢ͱࢦ෦ͷࠩͰڑΛٻΊΒΕΔ
21 23 24 26 2 3 2 22 25 Ұप͢Δͱۙͮ͘ߏͳͷͰ8ͷ༨Λ͑Αͦ͞͏✋
1 20 27
ೖྗͷύʔε
1 2 4 8 16 32 64 128
2 8 16 64 165 Λ 1 + 4 +
32 + 128 ʹղ͍ͨ͠ 1 4 32 128
2 8 16 64 1 4 32 128
21 23 24 26 20 22 25 27
165 = 27x1 + 26x0 + 25x1 + 24x0 +
23x0 + 22x1 + 21x0 + 20x1 21 23 24 26 20 22 25 27
165 = b10100101 21 23 24 26 20 22 25
27
21 23 24 26 20 22 25 27 ೖྗΛ2ਐͰද͢ͱɺ͕1ͷܻ͕࣮ઢͷҐஔΛࣔ͢
࣮ྫ
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); }
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); } ೖྗΛ2ਐʹมͯ͠ɺཱ͍ͬͯΔϏοτͷҐஔʢ0ʙ7ʣΛྻʹ͢Δɻ ྫͷ߹ $lines === [0, 2, 5, 7] ͱͳΔɻ͜Ε͕࣮ઢͷҐஔɻ ೖྗͷύʔε
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] ͱ͍͏ྻʹରͯ͠ɺཁૉؒͷ͔ࠩΒ࣮ઢؒͷڑΛٻΊΔͱɺ (2-0+8)%8=2, (5-2+8)%8=3, (7-5+8)%8=2, (0-7+8)%8=1 ͱͳΔɻ ڑ͕4ͷ߹ 2+ڑ-1 ͕ɺڑ͕ͦΕҎ֎ͷ߹ 3+ڑ-1 ͕ɻ ͷܭࢉ
https://github.com/ ttskch/nagoyaphp15
@ttskch ʘThanks!ʗ