solved(python): baekjoon 20040

Author: himitery

baekjoon/python/20040/__init__.py

@@ -0,0 +1,38 @@
+import sys
+
+read = lambda: sys.stdin.readline().rstrip()
+
+
+class Problem:
+    def __init__(self):
+        self.n, self.m = map(int, read().split())
+        self.data = [tuple(map(int, read().split())) for _ in range(self.m)]
+        self.parent = list(range(self.n))
+
+    def solve(self) -> None:
+        count = 0
+        for idx, (x, y) in enumerate(self.data):
+            if self.find_cycle(x, y):
+                count = idx + 1
+                break
+
+        print(count)
+
+    def find_cycle(self, x: int, y: int) -> bool:
+        root_x, root_y = self.find_root(x), self.find_root(y)
+        if root_x == root_y:
+            return True
+
+        self.parent[root_y] = root_x
+        return False
+
+    def find_root(self, x: int) -> int:
+        while self.parent[x] != x:
+            self.parent[x] = self.parent[self.parent[x]]
+            x = self.parent[x]
+
+        return x
+
+
+if __name__ == "__main__":
+    Problem().solve()

baekjoon/python/20040/main.py

@@ -0,0 +1,28 @@
+[
+  {
+    "input": [
+      "6 5",
+      "0 1",
+      "1 2",
+      "2 3",
+      "5 4",
+      "0 4"
+    ],
+    "expected": [
+      "0"
+    ]
+  },
+  {
+    "input": [
+      "6 5",
+      "0 1",
+      "1 2",
+      "1 3",
+      "0 3",
+      "4 5"
+    ],
+    "expected": [
+      "4"
+    ]
+  }
+]

baekjoon/python/20040/sample.json

@@ -0,0 +1,36 @@
+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()