๋ชฉ๋กAlgorithm๐ŸŒŠ/๋ฐฑ์ค€(BOJ) (4)

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[๋ฐฑ์ค€ / JAVA] 1717๋ฒˆ, ์ง‘ํ•ฉ์˜ ํ‘œํ˜„ (Union-Find)

๋ฌธ์ œ์ดˆ๊ธฐ์— n+1$n+1$๊ฐœ์˜ ์ง‘ํ•ฉ {0}, {1}, {2},…, {n} ์ด ์žˆ๋‹ค. ์—ฌ๊ธฐ์— ํ•ฉ์ง‘ํ•ฉ ์—ฐ์‚ฐ๊ณผ, ๋‘ ์›์†Œ๊ฐ€ ๊ฐ™์€ ์ง‘ํ•ฉ์— ํฌํ•จ๋˜์–ด ์žˆ๋Š”์ง€๋ฅผ ํ™•์ธํ•˜๋Š” ์—ฐ์‚ฐ์„ ์ˆ˜ํ–‰ํ•˜๋ ค๊ณ  ํ•œ๋‹ค.์ง‘ํ•ฉ์„ ํ‘œํ˜„ํ•˜๋Š” ํ”„๋กœ๊ทธ๋žจ์„ ์ž‘์„ฑํ•˜์‹œ์˜ค.์ž…๋ ฅ์ฒซ์งธ ์ค„์— n, m์ด ์ฃผ์–ด์ง„๋‹ค. m์€ ์ž…๋ ฅ์œผ๋กœ ์ฃผ์–ด์ง€๋Š” ์—ฐ์‚ฐ์˜ ๊ฐœ์ˆ˜์ด๋‹ค. ๋‹ค์Œ m๊ฐœ์˜ ์ค„์—๋Š” ๊ฐ๊ฐ์˜ ์—ฐ์‚ฐ์ด ์ฃผ์–ด์ง„๋‹ค. ํ•ฉ์ง‘ํ•ฉ์€ 0 a b์˜ ํ˜•ํƒœ๋กœ ์ž…๋ ฅ์ด ์ฃผ์–ด์ง„๋‹ค. ์ด๋Š” a๊ฐ€ ํฌํ•จ๋˜์–ด ์žˆ๋Š” ์ง‘ํ•ฉ๊ณผ, b๊ฐ€ ํฌํ•จ๋˜์–ด ์žˆ๋Š” ์ง‘ํ•ฉ์„ ํ•ฉ์นœ๋‹ค๋Š” ์˜๋ฏธ์ด๋‹ค. ๋‘ ์›์†Œ๊ฐ€ ๊ฐ™์€ ์ง‘ํ•ฉ์— ํฌํ•จ๋˜์–ด ์žˆ๋Š”์ง€๋ฅผ ํ™•์ธํ•˜๋Š” ์—ฐ์‚ฐ์€ 1 a b์˜ ํ˜•ํƒœ๋กœ ์ž…๋ ฅ์ด ์ฃผ์–ด์ง„๋‹ค. ์ด๋Š” a์™€ b๊ฐ€ ๊ฐ™์€ ์ง‘ํ•ฉ์— ํฌํ•จ๋˜์–ด ์žˆ๋Š”์ง€๋ฅผ ํ™•์ธํ•˜๋Š” ์—ฐ์‚ฐ์ด๋‹ค.์ถœ๋ ฅ1๋กœ ์‹œ์ž‘ํ•˜๋Š” ์ž…๋ ฅ์— ๋Œ€ํ•ด์„œ a์™€ b๊ฐ€ ๊ฐ™์€ ์ง‘ํ•ฉ์— ํฌํ•จ๋˜์–ด ์žˆ์œผ๋ฉด "YES" ๋˜๋Š”..