solved(python): baekjoon 2162

Author: himitery

baekjoon/python/2162/__init__.py

@@ -0,0 +1,61 @@
+import sys
+from collections import Counter
+
+read = lambda: sys.stdin.readline().rstrip()
+
+
+class Problem:
+    def __init__(self):
+        self.n = int(read())
+        self.lines = []
+        self.root = list(range(self.n))
+
+        for idx in range(self.n):
+            x1, y1, x2, y2 = tuple(map(int, read().split()))
+            self.lines.append(((x1, y1), (x2, y2)))
+
+    def solve(self) -> None:
+        for line_x in range(self.n - 1):
+            for line_y in range(line_x + 1, self.n):
+                (a, b), (c, d) = self.lines[line_x], self.lines[line_y]
+                if self.is_cross(a, b, c, d):
+                    self.union(line_x, line_y)
+
+        group = [self.find(num) for num in range(self.n)]
+        print(len(set(group)))
+        print(max(Counter(group).values()))
+
+    def union(self, x: int, y: int):
+        root_x, root_y = self.find(x), self.find(y)
+        if root_x != root_y:
+            self.root[root_y] = root_x
+
+    def find(self, num: int) -> int:
+        if num != self.root[num]:
+            self.root[num] = self.find(self.root[num])
+        return self.root[num]
+
+    def is_cross(self, a: tuple[int, int], b: tuple[int, int], c: tuple[int, int], d: tuple[int, int]) -> bool:
+        ccw_ab, ccw_cd = self.ccw((a, b, c)) * self.ccw((a, b, d)), self.ccw((c, d, a)) * self.ccw((c, d, b))
+
+        if ccw_ab == 0 and ccw_cd == 0:
+            return self.is_overlap(a, b, c, d)
+
+        return ccw_ab <= 0 and ccw_cd <= 0
+
+    def ccw(self, points: tuple[tuple[int, int], tuple[int, int], tuple[int, int]]) -> int:
+        (x1, y1), (x2, y2), (x3, y3) = points
+        result = (x2 - x1) * (y3 - y1) - (y2 - y1) * (x3 - x1)
+        return 0 if result == 0 else (result // abs(result))
+
+    def is_overlap(self, a: tuple[int, int], b: tuple[int, int], c: tuple[int, int], d: tuple[int, int]) -> bool:
+        return (
+            min(a[0], b[0]) <= max(c[0], d[0])
+            and min(c[0], d[0]) <= max(a[0], b[0])
+            and min(a[1], b[1]) <= max(c[1], d[1])
+            and min(c[1], d[1]) <= max(a[1], b[1])
+        )
+
+
+if __name__ == "__main__":
+    Problem().solve()

baekjoon/python/2162/main.py

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+[
+  {
+    "input": [
+      "3",
+      "1 1 2 3",
+      "2 1 0 0",
+      "1 0 1 1"
+    ],
+    "expected": [
+      "1",
+      "3"
+    ]
+  },
+  {
+    "input": [
+      "3",
+      "-1 -1 1 1",
+      "-2 -2 2 2",
+      "0 1 -1 0"
+    ],
+    "expected": [
+      "2",
+      "2"
+    ]
+  }
+]

baekjoon/python/2162/sample.json

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+import json
+import os.path
+import unittest
+from io import StringIO
+from unittest.mock import patch
+
+from parameterized import parameterized
+
+from main import Problem
+
+
+def load_sample(filename: str):
+    path = os.path.join(os.path.dirname(os.path.abspath(__file__)), filename)
+
+    with open(path, "r") as file:
+        return [(case["input"], case["expected"]) for case in json.load(file)]
+
+
+class TestCase(unittest.TestCase):
+    @parameterized.expand(load_sample("sample.json"))
+    def test_case(self, case: str, expected: list[str]):
+        # When
+        with (
+            patch("sys.stdin.readline", side_effect=case),
+            patch("sys.stdout", new_callable=StringIO) as output,
+        ):
+            Problem().solve()
+
+            result = output.getvalue().rstrip()
+
+        # Then
+        self.assertEqual("\n".join(expected), result)
+
+
+if __name__ == "__main__":
+    unittest.main()