\n3. \ubb38\uc81c \uc124\uba85<\/h2>\n
\ub2e4\uc74c \ubb38\uc81c\ub97c \ud1b5\ud574 \uadf8\ub798\ud504\uc758 \ud45c\ud604 \ubc29\uc2dd\uc744 \uc2e4\uc81c\ub85c \uc801\uc6a9\ud574\ubcf4\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n
\ubb38\uc81c: \uce5c\uad6c \ub124\ud2b8\uc6cc\ud06c<\/h3>\n
\ub2f9\uc2e0\uc740 N\uba85\uc758 \uce5c\uad6c\uac00 \uc788\ub294 \ub124\ud2b8\uc6cc\ud06c\ub97c \uad00\ub9ac\ud558\uace0 \uc788\uc2b5\ub2c8\ub2e4. \uce5c\uad6c \uad00\uacc4\ub294 \uc591\ubc29\ud5a5\uc774\uba70, \ub450 \uce5c\uad6c\uac00 \uc9c1\uc811\uc801\uc73c\ub85c \uc5f0\uacb0\ub418\uc5b4 \uc788\ub2e4\uba74 \uadf8\ub4e4\uc740 \uc11c\ub85c\uc758 \uce5c\uad6c\uc785\ub2c8\ub2e4. \uce5c\uad6c \uad00\uacc4\ub97c \uadf8\ub798\ud504\ub85c \ud45c\ud604\ud558\uace0, \ud2b9\uc815 \ub450 \uce5c\uad6c\uac00 \uac19\uc740 \uce5c\uad6c \uadf8\ub8f9\uc5d0 \uc18d\ud558\ub294\uc9c0 \ud655\uc778\ud558\ub294 \ud504\ub85c\uadf8\ub7a8\uc744 \uc791\uc131\ud558\uc138\uc694. \uce5c\uad6c \uadf8\ub8f9\uc740 \uac04\uc811\uc801\uc73c\ub85c \uc5f0\uacb0\ub41c \ubaa8\ub4e0 \uce5c\uad6c\ub97c \ud3ec\ud568\ud569\ub2c8\ub2e4.<\/p>\n
\uc785\ub825 \ud615\uc2dd:<\/p>\n
\nN (\uce5c\uad6c\uc758 \uc218)\nM (\uce5c\uad6c \uad00\uacc4\uc758 \uc218)\nM\uac1c\uc758 \uc904\uc5d0 \uac78\uccd0 \ub450 \uce5c\uad6c A\uc640 B (1 \u2264 A, B \u2264 N)\uac00 \uc8fc\uc5b4\uc9d1\ub2c8\ub2e4.\n <\/pre>\n\ucd9c\ub825 \ud615\uc2dd:<\/p>\n
\nA\uc640 B\uac00 \uac19\uc740 \uce5c\uad6c \uadf8\ub8f9\uc5d0 \uc18d\ud558\uba74 \"YES\"\ub97c, \uadf8\ub807\uc9c0 \uc54a\uc73c\uba74 \"NO\"\ub97c \ucd9c\ub825\ud569\ub2c8\ub2e4.\n <\/pre>\n<\/section>\n\n4. \ubb38\uc81c \ud480\uc774 \uacfc\uc815<\/h2>\n4.1. \uadf8\ub798\ud504 \uc0dd\uc131<\/h3>\n
\uba3c\uc800, \uc785\ub825\uc73c\ub85c \uc8fc\uc5b4\uc9c4 \uce5c\uad6c \uad00\uacc4\ub97c \ubc14\ud0d5\uc73c\ub85c \uadf8\ub798\ud504\ub97c \uc0dd\uc131\ud574\uc57c \ud569\ub2c8\ub2e4. \uc6b0\ub9ac\ub294 \uc778\uc811 \ub9ac\uc2a4\ud2b8\ub97c \uc0ac\uc6a9\ud558\uc5ec \uc774\ub97c \uad6c\ud604\ud558\uaca0\uc2b5\ub2c8\ub2e4. \ub2e4\uc74c\uc740 \uadf8\ub798\ud504 \uc0dd\uc131\uc744 \uc704\ud55c \uac04\ub2e8\ud55c \uc2a4\uc704\ud504\ud2b8 \ucf54\ub4dc\uc785\ub2c8\ub2e4.<\/p>\n
\nimport Foundation\n\n\/\/ \uadf8\ub798\ud504\ub97c \ud45c\ud604\ud558\uae30 \uc704\ud55c \uc778\uc811 \ub9ac\uc2a4\ud2b8\nvar graph: [Int: [Int]] = [:]\n\n\/\/ \uce5c\uad6c \uad00\uacc4\ub97c \ucd94\uac00\ud558\ub294 \ud568\uc218\nfunc addFriendRelation(friendA: Int, friendB: Int) {\n graph[friendA, default: []].append(friendB)\n graph[friendB, default: []].append(friendA)\n}\n\n\/\/ \uadf8\ub798\ud504 \uc0dd\uc131 \ud568\uc218\nfunc createGraph(N: Int, relations: [(Int, Int)]) {\n for (A, B) in relations {\n addFriendRelation(friendA: A, friendB: B)\n }\n}\n <\/code><\/pre>\n\uc704 \ucf54\ub4dc\ub294 \uac01 \uce5c\uad6c\ub97c \ud0a4\ub85c \ud558\uace0 \uc5f0\uacb0\ub41c \uce5c\uad6c\ub4e4\uc758 \ub9ac\uc2a4\ud2b8\ub97c \uac12\uc73c\ub85c \uac00\uc9c0\ub294 \ub515\uc154\ub108\ub9ac\ub97c \ub9cc\ub4e4\uc5b4 \uadf8\ub798\ud504\ub97c \uc0dd\uc131\ud569\ub2c8\ub2e4.<\/p>\n
4.2. \uce5c\uad6c \uadf8\ub8f9 \ucc3e\uae30<\/h3>\n
\uc774\uc81c \ub450 \uce5c\uad6c\uac00 \uac19\uc740 \uadf8\ub8f9\uc5d0 \uc18d\ud558\ub294\uc9c0 \ud655\uc778\ud558\uae30 \uc704\ud574 \uadf8\ub798\ud504 \ud0d0\uc0c9 \uc54c\uace0\ub9ac\uc998 \uc911 \ud558\ub098\ub97c \uc0ac\uc6a9\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uae4a\uc774 \uc6b0\uc120 \ud0d0\uc0c9(DFS) \ub610\ub294 \ub108\ube44 \uc6b0\uc120 \ud0d0\uc0c9(BFS)\ub97c \uc0ac\uc6a9\ud560 \uc218 \uc788\ub294\ub370, \uc5ec\uae30\uc11c\ub294 DFS\ub97c \uc120\ud0dd\ud558\uaca0\uc2b5\ub2c8\ub2e4. DFS\ub97c \ud1b5\ud574 \uc5f0\uad00\ub41c \uce5c\uad6c\ub4e4\uc744 \ubaa8\ub450 \ud0d0\uc0c9\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
\nfunc dfs(start: Int, visited: inout Set) {\n visited.insert(start)\n for friend in graph[start, default: []] {\n if !visited.contains(friend) {\n dfs(start: friend, visited: &visited)\n }\n }\n}\n\n\/\/ \ub450 \uce5c\uad6c\uac00 \uac19\uc740 \uadf8\ub8f9\uc5d0 \uc18d\ud558\ub294\uc9c0 \ud655\uc778\ud558\ub294 \ud568\uc218\nfunc areInSameGroup(friendA: Int, friendB: Int) -> Bool {\n var visited = Set()\n dfs(start: friendA, visited: &visited)\n return visited.contains(friendB)\n}\n <\/int><\/int><\/code><\/pre>\n4.3. \uc804\uccb4 \ud504\ub85c\uc138\uc2a4<\/h3>\n
\uc774\uc81c \uc804\uccb4 \uacfc\uc815\uc744 \ud1b5\ud569\ud558\uc5ec \ubb38\uc81c\ub97c \ud574\uacb0\ud574\ubcf4\uaca0\uc2b5\ub2c8\ub2e4. \uc785\ub825\uc744 \ubc1b\uace0, \uadf8\ub798\ud504\ub97c \uc0dd\uc131\ud558\uace0, \ub450 \uce5c\uad6c\uc758 \uad00\uacc4\ub97c \ud655\uc778\ud558\ub294 \ucf54\ub4dc\uc785\ub2c8\ub2e4.<\/p>\n
\nlet N = Int(readLine()!)! \/\/ \uce5c\uad6c\uc758 \uc218\nlet M = Int(readLine()!)! \/\/ \uce5c\uad6c \uad00\uacc4\uc758 \uc218\n\nvar relations = [(Int, Int)]()\n\nfor _ in 0..<\/m><\/code><\/pre>\n\uc704 \ucf54\ub4dc\ub294 \uc804\uccb4 \ud750\ub984\uc744 \ud1b5\ud574 \uce5c\uad6c \uad00\uacc4\ub97c \ud45c\ud604\ud558\uace0 \uac80\uc0ac\ud558\ub294 \ub85c\uc9c1\uc744 \uad6c\ud604\ud55c \uac83\uc785\ub2c8\ub2e4.<\/p>\n<\/section>\n\n5. \uacb0\ub860<\/h2>\n
\uc774\ubc88 \uac15\uc88c\ub97c \ud1b5\ud574 \uadf8\ub798\ud504\uc758 \ud45c\ud604 \ubc29\ubc95\uacfc \uae30\ubcf8\uc801\uc778 DFS \uc54c\uace0\ub9ac\uc998\uc744 \ud65c\uc6a9\ud558\uc5ec \ubb38\uc81c\ub97c \ud574\uacb0\ud558\ub294 \ubc29\ubc95\uc5d0 \ub300\ud574 \uc0b4\ud3b4\ubcf4\uc558\uc2b5\ub2c8\ub2e4. \uadf8\ub798\ud504\ub294 \ub2e4\uc591\ud55c \ubb38\uc81c\uc5d0 \uc801\uc6a9\ub420 \uc218 \uc788\ub294 \uc720\uc6a9\ud55c \uc790\ub8cc\uad6c\uc870\ub85c, \ucda9\ubd84\ud55c \uc5f0\uc2b5\uc744 \ud1b5\ud574 \uc219\uc9c0\ud560 \ud544\uc694\uac00 \uc788\uc2b5\ub2c8\ub2e4. \ucf54\ub529 \ud14c\uc2a4\ud2b8\uc5d0\uc11c\ub3c4 \uc774\ub7ec\ud55c \ubb38\uc81c\uac00 \uc885\uc885 \ucd9c\uc81c\ub418\ubbc0\ub85c, \ubb38\uc81c\ub97c \uc5ec\ub7ec \ubc88 \ud480\uc5b4\ubcf4\uba70 \uc2e4\ub825\uc744 \ud5a5\uc0c1\uc2dc\ud0a4\uae38 \ubc14\ub78d\ub2c8\ub2e4.<\/p>\n<\/section>\n