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๋ชฉ๋กleetcode 1721 (1)

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1721. Swapping Nodes in a Linked List [leetcode] | ๊ฐ’์ด ์•„๋‹Œ ๊ฐ์ฒด(๋…ธ๋“œ)๋ฅผ ์ง์ ‘ ๊ตํ™˜ ํ•ด๋ณด๊ธฐ

https://leetcode.com/problems/swapping-nodes-in-a-linked-list/description/๋ฌธ์ œ๋Š” ์œ„ ๋งํฌ ์ฐธ์กฐ ํ•ด๋‹น ๋ฌธ์ œ๋ฅผ ์ฒ˜์Œ ์ ‘๊ทผ ํ–ˆ์„ ๋•Œ ๊ฐ์ฒด๋ฅผ ๊ตํ™˜ํ•˜๋Š” ๊ฒƒ์€ ๋„ˆ๋ฌด ๋ณต์žกํ•ด ๋ณด์—ฌ ๊ฐ’๋งŒ ๊ตํ™˜ํ•˜๋Š” ๋ฐฉ์‹์œผ๋กœ ๋ฌธ์ œ๋ฅผ ํ•ด๊ฒฐํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค.์ดํ›„ ์ง์ ‘ ๊ฐ์ฒด๋ฅผ ๊ตํ™˜ํ•˜๋Š” ๋ฐฉ์‹์„ ํ•™์Šตํ•ด๋ณด์•˜๋‹ค.  ํ’€์ด ์š”์•ฝ1. ์—์ง€ ์ผ€์ด์Šค ์ฒ˜๋ฆฌ: ๋ฆฌ์ŠคํŠธ๊ฐ€ ๋น„์–ด์žˆ๊ฑฐ๋‚˜ ํ•˜๋‚˜์˜ ๋…ธ๋“œ๋งŒ ์žˆ๋Š” ๊ฒฝ์šฐ ๊ทธ๋Œ€๋กœ ๋ฐ˜ํ™˜2. dummy ๋…ธ๋“œ๋ฅผ ์ƒ์„ฑํ•˜์—ฌ head ๋…ธ๋“œ ๊ตํ™˜์„ ์ฒ˜๋ฆฌ3. 4๊ฐœ์˜ ํฌ์ธํ„ฐ ์‚ฌ์šฉ : prevFirst, first, prevSecond, second (๊ฐ๊ฐ ๊ตํ™˜ํ•  ๋‘ ๋…ธ๋“œ์™€ ๊ทธ ์ง์ „ ๋…ธ๋“œ๋“ค์„ ๊ฐ€๋ฆฌํ‚จ๋‹ค.)4. ์•ž์—์„œ k๋ฒˆ์งธ ๋…ธ๋“œ(first)์™€ ์ง์ „ ๋…ธ๋“œ(prevFirst) ์ฐพ๊ธฐ5. ๋’ค์—์„œ k๋ฒˆ์งธ ..