solved(python): baekjoon 5719

Author: himitery

baekjoon/python/5719/__init__.py

@@ -0,0 +1,68 @@
+import heapq
+import math
+import sys
+from collections import defaultdict, deque
+
+read = lambda: sys.stdin.readline().rstrip()
+
+
+class Problem:
+    def __init__(self):
+        self.n, self.m = map(int, read().split())
+        self.s, self.d = map(int, read().split())
+
+        self.graph = defaultdict(list[tuple[int, int]])
+        for _ in range(self.m):
+            u, v, p = map(int, read().split())
+            self.graph[u].append((v, p))
+
+    def solve(self) -> None:
+        result = self.dijkstra(self.s, self.remove_edges(self.dijkstra(self.s)))[self.d]
+        print(result if result != math.inf else -1)
+
+    def dijkstra(self, start_node: int, removed: list[set[int]] = None):
+        heap, dist, prev = (
+            [(0, start_node)],
+            [0 if x == start_node else math.inf for x in range(self.n)],
+            [[] for _ in range(self.n)],
+        )
+
+        while heap:
+            cost, node = heapq.heappop(heap)
+            if cost > dist[node]:
+                continue
+
+            for next_node, weight in self.graph[node]:
+                if removed and next_node in removed[node]:
+                    continue
+
+                if cost + weight < dist[next_node]:
+                    dist[next_node] = cost + weight
+                    prev[next_node] = [node]
+                    heapq.heappush(heap, (cost + weight, next_node))
+                elif removed is None and cost + weight == dist[next_node]:
+                    prev[next_node].append(node)
+
+        return prev if removed is None else dist
+
+    def remove_edges(self, prev: list[list[int]]) -> list[set[int]]:
+        queue, removed, visited = deque([self.d]), [set() for _ in range(self.n)], {self.d}
+
+        while queue:
+            node = queue.popleft()
+
+            for prev_node in prev[node]:
+                removed[prev_node].add(node)
+                if prev_node not in visited:
+                    visited.add(prev_node)
+                    queue.append(prev_node)
+
+        return removed
+
+
+if __name__ == "__main__":
+    while True:
+        try:
+            Problem().solve()
+        except (EOFError, ValueError):
+            break

baekjoon/python/5719/main.py

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+[
+  {
+    "input": [
+      "7 9",
+      "0 6",
+      "0 1 1",
+      "0 2 1",
+      "0 3 2",
+      "0 4 3",
+      "1 5 2",
+      "2 6 4",
+      "3 6 2",
+      "4 6 4",
+      "5 6 1",
+      "4 6",
+      "0 2",
+      "0 1 1",
+      "1 2 1",
+      "1 3 1",
+      "3 2 1",
+      "2 0 3",
+      "3 0 2",
+      "6 8",
+      "0 1",
+      "0 1 1",
+      "0 2 2",
+      "0 3 3",
+      "2 5 3",
+      "3 4 2",
+      "4 1 1",
+      "5 1 1",
+      "3 0 1",
+      "0 0"
+    ],
+    "expected": [
+      "5",
+      "-1",
+      "6"
+    ]
+  }
+]

baekjoon/python/5719/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,
+        ):
+            while True:
+                try:
+                    Problem().solve()
+                except StopIteration:
+                    break
+
+            result = output.getvalue().rstrip()
+
+        # Then
+        self.assertEqual("\n".join(expected), result)
+
+
+if __name__ == "__main__":
+    unittest.main()