solved(python): baekjoon 1916

Author: himitery

baekjoon/python/1916/__init__.py

@@ -0,0 +1,42 @@
+import heapq
+import math
+import sys
+from collections import defaultdict
+
+read = lambda: sys.stdin.readline().rstrip()
+
+
+class Problem:
+    def __init__(self):
+        self.n, self.m = int(read()), int(read())
+
+        self.graph = defaultdict(list[tuple[int, int]])
+        for src, dest, price in [map(int, read().split()) for _ in range(self.m)]:
+            self.graph[src].append((dest, price))
+
+        self.start, self.end = map(int, read().split())
+
+    def solve(self) -> None:
+        print(self.dijkstra(self.start, self.end))
+
+    def dijkstra(self, start: int, end: int) -> int:
+        heap, prices = [(0, start)], [0 if idx == start else math.inf for idx in range(self.n + 1)]
+
+        while heap:
+            current_price, current_city = heapq.heappop(heap)
+            if current_city == end:
+                break
+
+            if current_price > prices[current_city]:
+                continue
+
+            for next_city, price in self.graph[current_city]:
+                if current_price + price < prices[next_city]:
+                    prices[next_city] = current_price + price
+                    heapq.heappush(heap, (current_price + price, next_city))
+
+        return int(prices[end])
+
+
+if __name__ == "__main__":
+    Problem().solve()

baekjoon/python/1916/main.py

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+[
+  {
+    "input": [
+      "5",
+      "8",
+      "1 2 2",
+      "1 3 3",
+      "1 4 1",
+      "1 5 10",
+      "2 4 2",
+      "3 4 1",
+      "3 5 1",
+      "4 5 3",
+      "1 5"
+    ],
+    "expected": [
+      "4"
+    ]
+  }
+]

baekjoon/python/1916/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()