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
業務自動化をJavaとSeleniumとAWS Lambdaで実現した方法
greenflagproject
1
120
XP, Testing and ninja testing
m_seki
2
110
Kotlin エンジニアへ送る:Swift 案件に参加させられる日に備えて~似てるけど色々違う Swift の仕様 / from Kotlin to Swift
lovee
1
250
レガシーシステムの機能調査・開発におけるAI利活用
takuya_ohtonari
0
610
Datadog RUM 本番導入までの道
shinter61
1
310
PHP 8.4の新機能「プロパティフック」から学ぶオブジェクト指向設計とリスコフの置換原則
kentaroutakeda
1
270
The Evolution of Enterprise Java with Jakarta EE 11 and Beyond
ivargrimstad
1
830
Team topologies and the microservice architecture: a synergistic relationship
cer
PRO
0
920
「ElixirでIoT!!」のこれまでとこれから
takasehideki
0
370
データベースコネクションプール(DBCP)の変遷と理解
fujikawa8
1
270
XSLTで作るBrainfuck処理系
makki_d
0
210
エンジニア向け採用ピッチ資料
inusan
0
140
Featured
See All Featured
The Success of Rails: Ensuring Growth for the Next 100 Years
eileencodes
45
7.4k
[Rails World 2023 - Day 1 Closing Keynote] - The Magic of Rails
eileencodes
35
2.3k
Save Time (by Creating Custom Rails Generators)
garrettdimon
PRO
31
1.2k
How to Create Impact in a Changing Tech Landscape [PerfNow 2023]
tammyeverts
53
2.8k
Learning to Love Humans: Emotional Interface Design
aarron
273
40k
Gamification - CAS2011
davidbonilla
81
5.3k
Dealing with People You Can't Stand - Big Design 2015
cassininazir
367
26k
Statistics for Hackers
jakevdp
799
220k
Building Applications with DynamoDB
mza
95
6.5k
The Power of CSS Pseudo Elements
geoffreycrofte
77
5.8k
How to Ace a Technical Interview
jacobian
277
23k
It's Worth the Effort
3n
184
28k
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