solved(python): baekjoon 11266

Author: himitery

baekjoon/python/11266/__init__.py

@@ -0,0 +1,74 @@
+import sys
+from collections import defaultdict, deque
+
+read = lambda: sys.stdin.readline().rstrip()
+
+
+class Problem:
+    def __init__(self):
+        self.v, self.e = map(int, read().split())
+
+        self.graph = defaultdict(list[int])
+        for x, y in [map(int, read().split()) for _ in range(self.e)]:
+            self.graph[x].append(y)
+            self.graph[y].append(x)
+
+    def solve(self) -> None:
+        discovered, low, points, order = (
+            [-1] * (self.v + 1),
+            [-1] * (self.v + 1),
+            set(),
+            0,
+        )
+
+        for node in range(1, self.v + 1):
+            if discovered[node] == -1:
+                order = self.dfs(node, discovered, low, points, order)
+
+        print(len(points))
+        print(*sorted(list(points)))
+
+    def dfs(
+            self,
+            start_node: int,
+            discovered: list[int],
+            low: list[int],
+            points: set[int],
+            order: int,
+    ) -> int:
+        stack, root_children_count = deque([(start_node, 0, iter(self.graph[start_node]))]), 0
+
+        while stack:
+            current_node, parent, neighbors = stack[-1]
+
+            if discovered[current_node] == -1:
+                order += 1
+                discovered[current_node] = low[current_node] = order
+
+            for neighbor in neighbors:
+                if neighbor == parent:
+                    continue
+
+                if discovered[neighbor] != -1:
+                    low[current_node] = min(low[current_node], discovered[neighbor])
+                else:
+                    if parent == 0:
+                        root_children_count += 1
+                    stack.append((neighbor, current_node, iter(self.graph[neighbor])))
+                    break
+            else:
+                stack.pop()
+                if parent != 0:
+                    low[parent] = min(low[parent], low[current_node])
+
+                    if parent != start_node and low[current_node] >= discovered[parent]:
+                        points.add(parent)
+
+        if root_children_count > 1:
+            points.add(start_node)
+
+        return order
+
+
+if __name__ == "__main__":
+    Problem().solve()

baekjoon/python/11266/main.py

@@ -0,0 +1,18 @@
+[
+  {
+    "input": [
+      "7 7",
+      "1 4",
+      "4 5",
+      "5 1",
+      "1 6",
+      "6 7",
+      "2 7",
+      "7 3"
+    ],
+    "expected": [
+      "3",
+      "1 6 7"
+    ]
+  }
+]

baekjoon/python/11266/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()