So Hee Park Lee

Binary Tree_๋ถ€๋ถ„์ง‘ํ•ฉ ๋งŒ๋“ค๊ธฐ

๐Ÿ”ต ThingsILearned โœ”๏ธ ๋ถ€๋ถ„์ง‘ํ•ฉ์˜ ๊ฐœ์ˆ˜๋Š” 2^ ๊ณต์ง‘ํ•ฉ ๋นผ๋ฉด 2^-1 โœ… ๋ถ€๋ถ„์ง‘ํ•ฉ ๊ตฌํ•˜๊ธฐ n์ด ์ž…๋ ฅ๋˜๋ฉด ๋ถ€๋ถ„์ง‘ํ•ฉ์„ ๊ตฌํ•˜์„ธ์š”. ๋‹จ, ๊ณต์ง‘ํ•ฉ์€ ์ถœ๋ ฅํ•˜์ง€ ์•Š์Šต๋‹ˆ๋‹ค. //โญ๏ธinput: 3 //โญ๏ธoutput: 1 2 3 1 2 1 3 1 2 3 2 3 ๐ŸŸข ์ฝ”๋“œ class Main { static int n; ...

Recursion, Memoization_ํ”ผ๋ณด๋‚˜์น˜

๐Ÿ”ต ThingsILearned โœ”๏ธ ๋ฉ”๋ชจ์ด์ œ์ด์…˜ ์ปดํ“จํ„ฐ ํ”„๋กœ๊ทธ๋žจ์ด ๋™์ผํ•œ ๊ณ„์‚ฐ์„ ๋ฐ˜๋ณตํ•ด์•ผ ํ•  ๋•Œ, ์ด์ „์— ๊ณ„์‚ฐํ•œ ๊ฐ’์„ ๋ฉ”๋ชจ๋ฆฌ์— ์ €์žฅํ•จ์œผ๋กœ์จ ๋™์ผํ•œ ๊ณ„์‚ฐ์˜ ๋ฐ˜๋ณต ์ˆ˜ํ–‰์„ ์ œ๊ฑฐํ•˜์—ฌ ํ”„๋กœ๊ทธ๋žจ ์‹คํ–‰ ์†๋„๋ฅผ ๋น ๋ฅด๊ฒŒ ํ•˜๋Š” ๊ธฐ์ˆ  ๋™์  ๊ณ„ํš๋ฒ•์˜ ํ•ต์‹ฌ์ด ๋˜๋Š” ๊ธฐ์ˆ  https://soheeparklee.github.io/posts/DS-memoizati...

AWS S3์„œ๋ฒ„ ์—ฐ๋™ํ•˜๊ธฐ

โœ… AWS S3 Simple Storeage Servce, ์ฃผ๋กœ ํŒŒ์ผ ์„œ๋ฒ„๋กœ ์‚ฌ์šฉ โญ๏ธ Scalability: S3๋Š” ํŠธ๋ž˜ํ”ฝ์ด ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ์„œ๋ฒ„ ์ธํ”„๋ผ, ์šฉ๋Ÿ‰ ๋ณ€๊ฒฝ์„ ๋Œ€์‹  ์ฒ˜๋ฆฌํ•ด ์คŒ โญ๏ธ Durability: ์—ฌ๋Ÿฌ ์˜์—ญ์— ๋ฐ์ดํ„ฐ ๋ณต์‚ฌ๋ณธ์„ ์ €์žฅํ•ด ํ•œ ์˜์—ญ์ด ๋‹ค์šด๋˜์–ด๋„ ๋ฐ์ดํ„ฐ ๋ณต๊ตฌ ๊ฐ€๋Šฅ Bucket: ๋‹ค์ˆ˜์˜ ๊ฐ์ฒด๋ฅผ ๊ด€๋ฆฌํ•˜๋Š” ์ปจํ…Œ์ด๋„ˆ, ...

Recursion_์žฌ๊ท€ ํ•จ์ˆ˜

๐Ÿ”ต ThingsILearned โœ”๏ธ ์žฌ๊ท€ํ•จ์ˆ˜ ๋ฉˆ์ถ”๊ธฐ ํ•จ์ˆ˜ ๋‚ด๋ถ€์—์„œ ํ•จ์ˆ˜๊ฐ€ ์ž๊ธฐ ์ž์‹ ์„ ๋˜ ๋‹ค์‹œ ํ˜ธ์ถœ ์•ˆ ๋ฉˆ์ถ”๋Š” ์ฝ”๋“œ ๋ฌดํ•œ์œผ๋กœ DFS(3) โ–ถ๏ธ DFS(2) โ–ถ๏ธ DFS(1) โ–ถ๏ธ DFS(0) โ–ถ๏ธ DFS(-1) โ–ถ๏ธ DFS(-2) โ–ถ๏ธ DFS(-3)โ€ฆโ€ฆ ๋”ฐ๋ผ์„œ ์žฌ๊ท€ํ•จ์ˆ˜๋Š” ๋ฌด์กฐ๊ฑด if, else, return ์žฌ๊ท€๋ฅผ ๋ฉˆ์ถ”๋Š” ์กฐ๊ฑด์ด ๊ผญ ํ•„์š”ํ•˜๋‹ค ...

๊ฒฐ์ • ์•Œ๊ณ ๋ฆฌ์ฆ˜, ์ด๋ถ„ํƒ์ƒ‰_๋งˆ๊ตฌ๊ฐ„ ๋ฐฐ์น˜ํ•˜๊ธฐ

โœ… ๋งˆ๊ตฌ๊ฐ„์— ๋ง๋“ค์„ ๋ฐฐ์น˜ํ•  ๋•Œ, ๊ฐ€์žฅ ๊ฐ€๊นŒ์šด ๋ง์˜ ์ตœ๋Œ€ ๊ฑฐ๋ฆฌ๋ฅผ ๊ตฌํ•˜์„ธ์š”. ๋งˆ๊ตฌ๊ฐ„์ด ์ฃผ์–ด์ง‘๋‹ˆ๋‹ค. ๋งˆ๊ตฌ๊ฐ„์€ ์ขŒํ‘œ์œ„์— ์žˆ์Šต๋‹ˆ๋‹ค. 1 2 8 4 9 ๋ง์„ c๋งˆ๋ฆฌ๋ฅผ ๋งˆ๊ตฌ๊ฐ„์— ๋ฐฐ์น˜ํ•  ๋•Œ ๊ฐ€์žฅ ๊ฐ€๊นŒ์šด ๋‘ ๋ง ์‚ฌ์ด์˜ ๊ฑฐ๋ฆฌ๊ฐ€ ์ตœ๋Œ€๊ฐ€ ๋˜๋„๋ก ํ•˜์„ธ์š” ๊ฐ€์žฅ ๊ฐ€๊นŒ์šด ๋‘ ๋ง ์‚ฌ์ด์˜ ๊ฑฐ๋ฆฌ๊ฐ€ ์ตœ๋Œ€๊ฐ€ ๋  ๋•Œ ๊ทธ ๊ฑฐ๋ฆฌ๋ฅผ ์ถœ๋ ฅํ•˜์„ธ์š” package com.example.ct_i...

๊ฒฐ์ • ์•Œ๊ณ ๋ฆฌ์ฆ˜, ์ด๋ถ„ํƒ์ƒ‰_๋ฎค์ง๋น„๋””์˜ค

๐Ÿ”ต ThingsILearned โœ”๏ธ ๊ฒฐ์ • ์•Œ๊ณ ๋ฆฌ์ฆ˜ ๋‹ต์„ x๋ผ๊ณ  ์ƒ๊ฐํ•˜๊ณ  x๊ฐ€ ์œ ํšจํ•œ์ง€ ํ™•์ธํ•ด ๊ฐ€๋ฉด์„œ ๋” ์ข‹์€ ๋‹ต์„ ์ฐพ๋Š” ์•Œ๊ณ ๋ฆฌ์ฆ˜ ํŠน์ • ๋ฒ”์œ„ ์•ˆ์— x๊ฐ€ ์กด์žฌํ•œ๋‹ค๋Š” ํ™•์‹ ์ด ์žˆ์–ด์•ผ ํ•จ. ๋”ฐ๋ผ์„œ ๋ฌธ์ œ์˜ ๊ฒฝ์šฐ 1~9๊นŒ์ง€ 3๊ฐœ์˜ ๊ทธ๋ฃน์— ๋„ฃ์„ ๊ฒƒ์ธ๋ฐ, ์ตœ์†Œ 9๋ถ€ํ„ฐ ์ตœ๋Œ€ 45(1๋ถ€ํ„ฐ 9๊นŒ์ง€์˜ ํ•ฉ)์‚ฌ์ด์— ๋‹ต์ด ์žˆ์„ ๊ฒƒ์ด๋ฏ€๋กœ 9~45์‚ฌ์ด์—์„œ ๊ฒฐ์ •์•Œ๊ณ ๋ฆฌ์ฆ˜...