Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
おしゃれなアルゴリズム
Search
eTakazawa
February 22, 2020
Programming
7
4.9k
おしゃれなアルゴリズム
本スライドは某LT用に作成しました.厳密性より,非競プロerに向けて面白さを重視しています.
過去問題の解説です.
eTakazawa
February 22, 2020
Tweet
Share
More Decks by eTakazawa
See All by eTakazawa
感動するアルゴリズム
etakazawa
0
180
Other Decks in Programming
See All in Programming
Storybookの情報をMCPサーバー化する
shota_tech
3
1.1k
VibeCoding時代のエンジニアリング
daisuketakeda
0
200
ComposeでのPicture in Picture
takathemax
0
140
JAWS DAYS 2025 re_Cheers: WEB
komakichi
0
120
ぽちぽち選択するだけでOSSを読めるVSCode拡張機能
ymbigo
14
6.3k
生成AIで知るお願いの仕方の難しさ
ohmori_yusuke
1
120
音声プラットフォームのアーキテクチャ変遷から学ぶ、クラウドネイティブなバッチ処理 (20250422_CNDS2025_Batch_Architecture)
thousanda
0
420
Golangci-lint v2爆誕: 君たちはどうすべきか
logica0419
1
260
カウシェで Four Keys の改善を試みた理由
ike002jp
1
140
MySQL初心者が311個のカラムにNot NULL制約を追加していってALTER TABLEについて学んだ話
hatsu38
2
140
はじめてのPDFKit.pdf
shomakato
0
100
開発者フレンドリーで顧客も満足?Platformの秘密
algoartis
0
220
Featured
See All Featured
Adopting Sorbet at Scale
ufuk
76
9.4k
Cheating the UX When There Is Nothing More to Optimize - PixelPioneers
stephaniewalter
280
13k
VelocityConf: Rendering Performance Case Studies
addyosmani
329
24k
Stop Working from a Prison Cell
hatefulcrawdad
268
20k
Dealing with People You Can't Stand - Big Design 2015
cassininazir
367
26k
CSS Pre-Processors: Stylus, Less & Sass
bermonpainter
357
30k
No one is an island. Learnings from fostering a developers community.
thoeni
21
3.3k
Let's Do A Bunch of Simple Stuff to Make Websites Faster
chriscoyier
507
140k
How STYLIGHT went responsive
nonsquared
100
5.5k
jQuery: Nuts, Bolts and Bling
dougneiner
63
7.7k
Become a Pro
speakerdeck
PRO
28
5.3k
YesSQL, Process and Tooling at Scale
rocio
172
14k
Transcript
͓͠ΌΕͳΞϧΰϦζϜ @utsubo_21 ※ ຊεϥΠυLT༻ʹ࡞͠·ͨ͠ ɹݫີੑΑΓɼඇڝϓϩerʹ͚ͯ໘ന͞Λॏࢹ͍ͯ͠·͢
ࠓ·Ͱղ͍ͨ ΞϧΰϦζϜͷͷத͔Β
ಛʹ͓͠Ζ͔ͬͨΛ pickup
• মΛ͍ͯ͠·͢ • ॏͳ͍ͬͯΔ෦͕ੜম͚ʹ • ͍͔ͭ͘ΛऔΓআ͘͜ͱͰ Ͱ͖Δ͚ͩ৯ΒΕΔ෦Λ͍ͨ͘͠ Question
* CODE FESTIVAL 2015 ຊઓ মͷୡਓ
• মΛ͍ͯ͠·͢ • ॏͳ͍ͬͯΔ෦͕ੜম͚ʹ • ͍͔ͭ͘ΛऔΓআ͘͜ͱͰ Ͱ͖Δ͚ͩ৯ΒΕΔ෦Λ͍ͨ͘͠ Question
* CODE FESTIVAL 2015 ຊઓ মͷୡਓ
• মΛ͍ͯ͠·͢ • ॏͳ͍ͬͯΔ෦͕ੜম͚ʹ • ͍͔ͭ͘ΛऔΓআ͘͜ͱͰ Ͱ͖Δ͚ͩ৯ΒΕΔ෦Λ͍ͨ͘͠ Question
* CODE FESTIVAL 2015 ຊઓ মͷୡਓ
• মΛ͍ͯ͠·͢ • ॏͳ͍ͬͯΔ෦͕ੜম͚ʹ • ͍͔ͭ͘ΛऔΓআ͘͜ͱͰ Ͱ͖Δ͚ͩ৯ΒΕΔ෦Λ͍ͨ͘͠ Question
* CODE FESTIVAL 2015 ຊઓ মͷୡਓ
Question • ೖྗ - (Ґஔɼ͞) × Nݸ ( N
≦ 10^5 ) - ͷ͞ M ( M ≦ 10^5 ) • త - ֤ʹ͍ͭͯম͔͘ম͔ͳ͍͔બͼɼ ͕ॏͳΒͣম͚Δ͞ͷ૯Λ࠷େԽ͠ग़ྗ 1 2 3
Question • ೖྗ - (Ґஔɼ͞) × Nݸ ( N
≦ 10^5 ) - ͷ͞ M ( M ≦ 10^5 ) • త - ֤ʹ͍ͭͯম͔͘ম͔ͳ͍͔બͼɼ ͕ॏͳΒͣম͚Δ͞ͷ૯Λ࠷େԽ͠ग़ྗ 1 2 3
Question • ೖྗ - (Ґஔɼ͞) × Nݸ ( N
≦ 10^5 ) - ͷ͞ M ( M ≦ 10^5 ) • త - ֤ʹ͍ͭͯম͔͘ম͔ͳ͍͔બͼɼ ͕ॏͳΒͣম͚Δ͞ͷ૯Λ࠷େԽ͠ग़ྗ 1 2 3
͏গ͠ෳࡶͳྫ ྫɽ
͏গ͠ෳࡶͳྫ ؒͷґଘ͕૿͑ɼ͍͠… ྫɽ
• ”͕ॏͳ͍ͬͯΔ” or ”Կͳ͍” ۠ؒ ͕͞Ք͛ͳ͍ • ”શମͷ͞M
ʔ ম͚ͳ͍۠ؒͷ͞” Ͱ͕͑ग़Δ ղ๏Λࢧ͑Δߟ͑ํ ম͚Δ෦Λ͘ → ম͚ͳ͍෦Λ͘
ղ๏ ͋ΔͷબͼํΛͨ࣌͠ͷ ম͚ͳ͍෦ͷ͞ΛΓ͍ͨ 1 2 3
ղ๏ ఱ࠽తͳͻΒΊ͖Ͱ ͷ͞ʹ߹ΘͤͯҹΛॻ͍ͯΈΔ
ղ๏ 1 2 3 ఱ࠽తͳͻΒΊ͖Ͱ ͷ͞ʹ߹ΘͤͯҹΛॻ͍ͯΈΔ
ղ๏ ͞Βʹఱ࠽తͳͻΒΊ͖Ͱ ”Կͳ͍” ෦Λද͢ҹΛՃ
ղ๏ ࠨ͔ΒӈҹΛḷͬͯΈΔ
ղ๏ ྫ͑ɼͷܦ࿏
ղ๏ ɹɹͷΈΛম͘߹Λදݱ ʢͱ”Կͳ͍”۠ؒ 4ͭʣ 1 1 ”Կͳ͍”۠ؒ
ղ๏ “Կͳ͍”۠ؒͷ͞ΛΓ͍ͨ ʢ㲎 શମͷ͞ʔম͚ͳ͍෦ͷ͞ʹম͚Δ͞ʣ
ղ๏ ҹʹίετΛ༩ 1 1 1 1 1 1
1 1 0 0 0
ղ๏ ܦ࿏্ͷҹͷίετͷ૯ ʹ ম͚ͳ͍෦(Կͳ͍෦)ͷ͞ ʹͳ͍ͬͯΔ 1 1 1
1 1 1 1 1 0 0 0
ղ๏ ”ॏͳ͍ͬͯΔ” ෦Ͳ͏දݱ͢Δ͔
ղ๏ ”ॏͳ͍ͬͯΔ” ෦Ͳ͏දݱ͢Δ͔ → ٯ͖ͷҹΛுΓ·͢ʢίετ1ʣ 1 1 1
ղ๏ ઌͱಉ༷ʹࠨ͔ΒӈҹΛḷΔ
ղ๏ ྫ͑ɼͷܦ࿏
ղ๏ 1 1 1 1 1 2 ɹɹͱɹɹΛম͘߹Λදݱ
1 2 ”Կͳ͍”۠ؒ ”ॏͳ͍ͬͯΔ”۠ؒ
ղ๏ 1 1 1 1 ম͚ͳ͍۠ؒͷ͞ 4 ”Կͳ͍”۠ؒ
”ॏͳ͍ͬͯΔ”۠ؒ
ղ๏ ·ͱΊ 1 1 1 1 1 1
1 1 1 1 1 ࠨ͔Βӈͷܦ࿏্ͷίετͷ૯ ʹ ম͚ͳ͍෦ͷ͞
ղ๏ ·ͱΊ 1 1 1 1 1 1
1 1 1 1 1 ͭ·Γɼࠨ͔Βӈͷ࠷ܦ࿏ ʹ ম͚ͳ͍෦ͷ͕͞࠷খͷͷબͼํ
ղ๏ ·ͱΊ 1 1 1 1 1 1
1 1 1 1 1 ͭ·Γɼ࠷ܦ࿏͕͔Εྑ͍ → ؆୯ʂ
ղ๏ ·ͱΊ 1 1 1 1 1 1
1 1 1 1 1 ͭ·Γɼ࠷ܦ࿏͕͔Εྑ͍ → ؆୯ʂ ܭࢉྔతʹɿ શ୳ࡧ O(2^N) → ຊख๏ O((M+N)logM)
͋ͱ͕͖ • ࠷ܦ࿏ʹؼணͰ͖ͯ࠷ߴʹ͓͠ΌΕ - মʹߦ͘ͱ͖ࢥ͍ग़ͯ͠Ͷ • ໘നΈΛײͨ͡ํڝϓϩ͍ͬͯͩ͘͞ • ࠷େԽΛ͢Δ࣌Կ͔ͷ࠷খԽʹ ஔ͖͑ΒΕͳ͍͔ߟ͑Δ
- “࠷େԽΛ࠷খԽʹมܗͯ͠ɼ࠷খΧοτʹؼண” ׂͱయܕΒ͍͠ʢࢀߟɿ೩͢ຒΊΔʣ https://www.slideshare.net/shindannin/project-selection-problem
͓·͚ • ൈ͚͍ͯΔେࣄͳߟ - ઌͷܦ࿏Ͱɼ3ຕҎ্͕ॏͳΔબͼํΛ දݱͰ͖ͳ͍ - ॏͳͬͨ෦Λ༨ܭʹίετͱͯ͠Χϯτͯ͠ ͠·͏ɽ͕ɼͦͦ3ຕҎ্ॏͳΔͷબͼํ ɼ࠷దղʹͳΓಘͳ͍
• ެࣜϖʔδͷղઆΛಡΜͰ͍ͩ͘͞ • ࢲ͕ॻ͍ͨίʔυͪ͜Β https://www.slideshare.net/chokudai/code-festival-2015-final https://code-festival-2015-final-open.contest.atcoder.jp/submissions/10197952