\n\uc548\ub155\ud558\uc138\uc694! \uc774\ubc88 \ud3ec\uc2a4\ud2b8\uc5d0\uc11c\ub294 \uc2a4\uc704\ud504\ud2b8\ub97c \ud65c\uc6a9\ud558\uc5ec \ucde8\uc5c5\uc6a9 \ucf54\ub529\ud14c\uc2a4\ud2b8\uc5d0\uc11c \uc790\uc8fc \ucd9c\uc81c\ub418\ub294 ‘\uc120\ubd84\uc758 \uad50\ucc28 \uc5ec\ubd80 \uad6c\ud558\uae30’ \ubb38\uc81c\ub97c \ud480\uc5b4\ubcf4\uaca0\uc2b5\ub2c8\ub2e4. \uc774 \ubb38\uc81c\ub97c \ud1b5\ud574 \uc54c\uace0\ub9ac\uc998\uc758 \uae30\ubcf8 \uac1c\ub150\uc744 \uc774\ud574\ud558\uace0, \uc5b4\ub5bb\uac8c \ubb38\uc81c\ub97c \ud574\uacb0\ud560 \uc218 \uc788\uc744\uc9c0 \ub2e4\ub904\ubcf4\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n<\/header>\n\n\ubb38\uc81c \uc124\uba85<\/h2>\n
\uc8fc\uc5b4\uc9c4 \ub450 \uc120\ubd84 AB\uc640 CD\uac00 \uc8fc\uc5b4\uc84c\uc744 \ub54c, \uc774 \ub450 \uc120\ubd84\uc774 \uad50\ucc28\ud558\ub294\uc9c0\ub97c \ud310\ubcc4\ud558\ub294 \ubb38\uc81c\uc785\ub2c8\ub2e4. \uc5ec\uae30\uc11c \uc120\ubd84 AB\ub294 \uc810 A(x1, y1)\uc640 \uc810 B(x2, y2)\ub85c \uc774\ub8e8\uc5b4\uc9c0\uace0, \uc120\ubd84 CD\ub294 \uc810 C(x3, y3)\uc640 \uc810 D(x4, y4)\ub85c \uc774\ub8e8\uc5b4\uc9d1\ub2c8\ub2e4. \uc5ec\ub7ec\ubd84\uc758 \ubaa9\ud45c\ub294 AB\uc640 CD\uac00 \uc11c\ub85c \uad50\ucc28\ud558\ub294\uc9c0 \ud655\uc778\ud558\uace0, \uadf8 \uacb0\uacfc\ub97c Boolean \uac12\uc73c\ub85c \ubc18\ud658\ud558\ub294 \uac83\uc785\ub2c8\ub2e4.<\/p>\n
\uc120\ubd84\uc774 \uc11c\ub85c \uad50\ucc28\ud558\ub294 \uc870\uac74\uc740 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4:<\/p>\n
\n- \uc11c\ub85c \ub2e4\ub978 \uc120\ubd84\uc774 \uc11c\ub85c\ub97c \uac00\ub85c\ub9c9\ub294 \uacbd\uc6b0<\/li>\n
- \ub05d\uc810\uc774 \uc120\ubd84\uc758 \uc704\uc5d0 \ub193\uc778 \uacbd\uc6b0<\/li>\n<\/ul>\n<\/section>\n\n
\ubb38\uc81c \uc811\uadfc \ubc29\ubc95<\/h2>\n
\uc774 \ubb38\uc81c\ub97c \ud574\uacb0\ud558\uae30 \uc704\ud574\uc11c\ub294 \uae30\ud558\ud559\uc801 \uc131\uc9c8\uc744 \uc774\uc6a9\ud574\uc57c \ud569\ub2c8\ub2e4. \uc77c\ubc18\uc801\uc73c\ub85c \ub450 \uc120\ubd84\uc774 \uad50\ucc28\ud558\ub294\uc9c0 \uc5ec\ubd80\ub97c \ud310\ub2e8\ud558\uae30 \uc704\ud574, \uc120\ud615 \ubc29\uc2dd\uacfc \uad50\ucc28 \uac80\uc99d\uc744 \uc0ac\uc6a9\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uae30\ubcf8 \uc544\uc774\ub514\uc5b4\ub294 \uac01 \uc120\ubd84\uc744 \uad6c\uc131\ud558\ub294 \uc810\ub4e4\uc758 \ubc30\uc5f4\uc744 \uac16\uace0, \ub450 \uc120\ubd84\uc774 \ubc29\uc815\uc2dd\uc73c\ub85c \ud45c\ud604\ub420 \uc218 \uc788\ub3c4\ub85d \ud558\ub294 \uac83\uc785\ub2c8\ub2e4.<\/p>\n
\uc120\uc758 \uad50\ucc28 \uc5ec\ubd80\ub97c \ud310\ub2e8\ud558\ub294 \uae30\ubcf8 \uc6d0\ub9ac\ub294 \ubca1\ud0c0\uc758 \ubc29\ud5a5\uc744 \uc774\uc6a9\ud574 \uac01 \uc120\ubd84\uc774 \uc11c\ub85c\ub97c \uac00\ub85c\ub9c9\ub294\uc9c0\ub97c \ud655\uc778\ud558\ub294 \uac83\uc785\ub2c8\ub2e4. \uac01\uac01\uc758 \uc120\ubd84\uc744 \uc815\uc758\ud55c \ud6c4, \uc774\ub4e4\uc774 \uad50\ucc28\ud558\ub294\uc9c0\ub97c \ud310\ubcc4\ud558\ub294 \ud568\uc218\ub97c \ub9cc\ub4e4\uc5b4\uc57c \ud569\ub2c8\ub2e4.<\/p>\n<\/section>\n\n\uc54c\uace0\ub9ac\uc998 \uc124\uacc4<\/h2>\n
\uba3c\uc800, \ub450 \uc120\ubd84\uc758 \ubc29\ud5a5\uc744 \uad6c\ud558\ub294 \ubc29\ubc95\uc744 \uc54c\uc544\ubd05\uc2dc\ub2e4. \uc8fc\uc5b4\uc9c4 \ub450 \uc810 A(x1, y1), B(x2, y2)\uc640 C(x3, y3), D(x4, y4)\uac00 \uc788\ub2e4\uace0 \uac00\uc815\ud569\ub2c8\ub2e4. \uc6b0\ub9ac\ub294 \ud06c\ub85c\uc2a4 \ud504\ub85c\ub355\ud2b8\ub97c \uc774\uc6a9\ud558\uc5ec \ub450 \uc810\uc758 \uc0c1\ub300\uc801 \uc704\uce58\ub97c \uad6c\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
\ud06c\ub85c\uc2a4 \ud504\ub85c\ub355\ud2b8\ub294 \ub2e4\uc74c\uacfc \uac19\uc774 \uc815\uc758\ub429\ub2c8\ub2e4:<\/p>\n
\n (B - A) \u00d7 (D - A) \n <\/pre>\n\uc5ec\uae30\uc11c \ubca1\ud130\uc758 \ud06c\ub85c\uc2a4 \ud504\ub85c\ub355\ud2b8\ub97c \ud1b5\ud574 \ub450 \uc120\ubd84\uc758 \ubc29\ud5a5\uc131\uc744 \uc54c \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ub2e4\uc74c \ub2e8\uacc4\ub294 \uac01 \uc120\ubd84\uc774 \uad50\ucc28\ud558\ub294\uc9c0 \uc5ec\ubd80\ub97c \ud655\uc778\ud558\ub294 \uac83\uc785\ub2c8\ub2e4.<\/p>\n
\uad6c\ud604\ud560 \ud568\uc218\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4:<\/p>\n
\n- \ub450 \uc810\uc758 \ud06c\ub85c\uc2a4 \ud504\ub85c\ub355\ud2b8\ub97c \uacc4\uc0b0\ud569\ub2c8\ub2e4.<\/li>\n
- \uacb0\uacfc\uac12\uc744 \ubc14\ud0d5\uc73c\ub85c \uc120\ubd84\uc758 \uad50\ucc28 \uc5ec\ubd80\ub97c \ud310\ubcc4\ud569\ub2c8\ub2e4.<\/li>\n
- \uac01 \uacbd\uc6b0\uc5d0 \ub530\ub77c Boolean \uac12\uc744 \ubc18\ud658\ud569\ub2c8\ub2e4.<\/li>\n<\/ol>\n<\/section>\n\n
\uc2a4\uc704\ud504\ud2b8 \ucf54\ub4dc \uc608\uc81c<\/h2>\n
\uc774\uc81c \uc704\uc758 \uc54c\uace0\ub9ac\uc998\uc744 \ubc14\ud0d5\uc73c\ub85c \uc2a4\uc704\ud504\ud2b8 \uc5b8\uc5b4\ub85c \ucf54\ub4dc\ub97c \uc791\uc131\ud574 \ubcf4\uaca0\uc2b5\ub2c8\ub2e4.<\/p>\n
\n \n struct Point {\n var x: Double\n var y: Double\n }\n\n func orientation(p: Point, q: Point, r: Point) -> Int {\n let val = (q.y - p.y) * (r.x - q.x) - (q.x - p.x) * (r.y - q.y)\n if val == 0 { return 0 \/\/ Collinear\n } else if val > 0 { return 1 \/\/ Clockwise\n } else { return 2 \/\/ Counterclockwise\n }\n }\n\n func doIntersect(p1: Point, q1: Point, p2: Point, q2: Point) -> Bool {\n let o1 = orientation(p: p1, q: q1, r: p2)\n let o2 = orientation(p: p1, q: q1, r: q2)\n let o3 = orientation(p: p2, q: q2, r: p1)\n let o4 = orientation(p: p2, q: q2, r: q1)\n\n if o1 != o2 && o3 != o4 {\n return true\n }\n\n \/\/ Collinear cases\n return false\n }\n\n \/\/ \uc608\uc2dc\n let p1 = Point(x: 1, y: 1)\n let q1 = Point(x: 10, y: 1)\n let p2 = Point(x: 1, y: 2)\n let q2 = Point(x: 10, y: 2)\n\n if doIntersect(p1: p1, q1: q1, p2: p2, q2: q2) {\n print(\"\uad50\ucc28\ud569\ub2c8\ub2e4.\")\n } else {\n print(\"\uad50\ucc28\ud558\uc9c0 \uc54a\uc2b5\ub2c8\ub2e4.\")\n }\n <\/code>\n <\/pre>\n\uc704 \ucf54\ub4dc\ub294 \uc8fc\uc5b4\uc9c4 \ub450 \uc120\ubd84\uc774 \uc0c1\ud638 \uad50\ucc28\ud558\ub294\uc9c0\ub97c \ud310\ub2e8\ud558\uc5ec \uacb0\uacfc\ub97c \ucd9c\ub825\ud569\ub2c8\ub2e4. \uc0ac\uc6a9\ud55c \ubc29\ubc95\uc740 orientation \ud568\uc218\ub85c \uac01 \ubc29\ud5a5\uc744 \uacc4\uc0b0\ud558\uace0 doIntersect \ud568\uc218\uc5d0\uc11c \uad50\ucc28 \uc5ec\ubd80\ub97c \ud655\uc778\ud569\ub2c8\ub2e4.<\/p>\n<\/section>\n\n\uc54c\uace0\ub9ac\uc998\uc758 \ucd5c\uc801\ud654<\/h2>\n
\uc544\ub798\ub294 \uc120\ubd84 \uac04 \uad50\ucc28 \uc5ec\ubd80\ub97c \ud655\uc778\ud558\uae30 \uc704\ud574 \ud560 \uc218 \uc788\ub294 \ucd5c\uc801\ud654 \uae30\uc220\uc785\ub2c8\ub2e4:<\/p>\n
\n- \ube44\uad50\uc801 \uac04\ub2e8\ud55c \uc120\ud615 \uac80\uc0c9 \uc54c\uace0\ub9ac\uc998\uc744 \uad6c\ud604\ud558\uc5ec \uad50\ucc28 \uc5ec\ubd80\ub97c \ube60\ub974\uac8c \ud310\ubcc4<\/li>\n
- \ud3ec\uc778\ud2b8\uac00 \uc120\ubd84\uc758 \ub05d\uc810\uacfc \uc77c\uce58\ud558\ub294 \uacbd\uc6b0\ub97c \ucc98\ub9ac\ud558\uae30 \uc704\ud55c \ucd94\uac00 \ub85c\uc9c1<\/li>\n
- \uc815\ub82c\ub41c \ud3ec\uc778\ud2b8\ub4e4\uc744 \uc774\uc6a9\ud558\uc5ec \ub300\ubd80\ubd84\uc758 \uacbd\uc6b0 \uc22b\uc790\uc801\uc778 \ud6a8\uc728\uc131 \ud5a5\uc0c1<\/li>\n<\/ul>\n<\/section>\n\n
\uacb0\ub860<\/h2>\n
\uc774\ubc88 \uac15\uc88c\uc5d0\uc11c\ub294 \uc2a4\uc704\ud504\ud2b8\ub97c \ud65c\uc6a9\ud558\uc5ec \uc120\ubd84\uc758 \uad50\ucc28 \uc5ec\ubd80\ub97c \ud310\ub2e8\ud558\ub294 \uc54c\uace0\ub9ac\uc998 \ubb38\uc81c\ub97c \ud480\uc5b4\ubcf4\uc558\uc2b5\ub2c8\ub2e4. \uc120\ubd84 \uad50\ucc28 \ubb38\uc81c\ub294 \ub2e4\uc591\ud55c \uc0c1\ud669\uc5d0\uc11c \uc720\uc6a9\ud558\uac8c \uc0ac\uc6a9\ub420 \uc218 \uc788\uc73c\uba70, \uc54c\uace0\ub9ac\uc998 \ubb38\uc81c \ud574\uacb0 \ub2a5\ub825\uc744 \ud5a5\uc0c1\uc2dc\ud0a4\ub294 \ub370 \uae30\uc5ec\ud569\ub2c8\ub2e4. \uc2e4\uc81c \uba74\uc811\uc5d0\uc11c\ub294 \uc774\uc640 \uc720\uc0ac\ud55c \ubb38\uc81c\ub97c \uc790\uc8fc \uc811\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ub530\ub77c\uc11c, \uc774\ub7f0 \ubb38\uc81c\ub97c \ud1b5\ud574 \ub2e4\uc591\ud55c \ud574\uacb0 \uc804\ub7b5\uc744 \uc5f0\uc2b5\ud558\ub294 \uac83\uc774 \uc911\uc694\ud569\ub2c8\ub2e4.<\/p>\n
\ub2e4\uc74c \ud3ec\uc2a4\ud2b8\uc5d0\uc11c\ub294 \ub2e4\ub978 \uc8fc\uc81c\uc758 \uc54c\uace0\ub9ac\uc998 \ubb38\uc81c\ub97c \ub2e4\ub8f0 \uc608\uc815\uc785\ub2c8\ub2e4. \ub9ce\uc740 \uad00\uc2ec \ubd80\ud0c1\ub4dc\ub9bd\ub2c8\ub2e4!<\/p>\n<\/section>\n