solved(python): baekjoon 1987

Author: himitery

baekjoon/python/1987/__init__.py

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+import sys
+from collections import deque
+
+read = lambda: sys.stdin.readline().rstrip()
+
+
+class Problem:
+    def __init__(self):
+        self.r, self.c = map(int, read().split())
+        self.matrix = [list(read()) for _ in range(self.r)]
+
+    def solve(self) -> None:
+        print(self.dfs())
+
+    def dfs(self) -> int:
+        stack, cache, max_depth = (
+            deque([((0, 0), 1, 1 << ord(self.matrix[0][0]) - ord("A"))]),
+            {row: {col: set() for col in range(self.c)} for row in range(self.r)},
+            1,
+        )
+        cache[0][0].add(1 << ord(self.matrix[0][0]) - ord("A"))
+
+        while stack:
+            (x, y), depth, visited = stack.pop()
+            if depth > max_depth:
+                max_depth = depth
+
+            if max_depth == min(self.r * self.c, 26):
+                return max_depth
+
+            for dx, dy in [(0, -1), (0, 1), (-1, 0), (1, 0)]:
+                nx, ny = x + dx, y + dy
+
+                if 0 <= nx < self.c and 0 <= ny < self.r:
+                    next_token_code = ord(self.matrix[ny][nx]) - ord("A")
+
+                    if visited & (1 << next_token_code) == 0:
+                        mask = visited | (1 << next_token_code)
+
+                        if mask not in cache[ny][nx]:
+                            cache[ny][nx].add(mask)
+                            stack.append(((nx, ny), depth + 1, mask))
+
+        return max_depth
+
+
+if __name__ == "__main__":
+    Problem().solve()

baekjoon/python/1987/main.py

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+[
+  {
+    "input": [
+      "2 4",
+      "CAAB",
+      "ADCB"
+    ],
+    "expected": [
+      "3"
+    ]
+  },
+  {
+    "input": [
+      "3 6",
+      "HFDFFB",
+      "AJHGDH",
+      "DGAGEH"
+    ],
+    "expected": [
+      "6"
+    ]
+  },
+  {
+    "input": [
+      "5 5",
+      "IEFCJ",
+      "FHFKC",
+      "FFALF",
+      "HFGCF",
+      "HMCHH"
+    ],
+    "expected": [
+      "10"
+    ]
+  }
+]

baekjoon/python/1987/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()