[2025-05-22] gwangseok #485

BaekJoon/11779/gwangseok.py

@@ -0,0 +1,51 @@
+# 간선이 모두 양수
+# 한 노드에서 다른 한 노드로 가는 최소한의 거리
+# 다익스트라 알고리즘
+
+import sys
+read_line = sys.stdin.readline
+
+import heapq
+from collections import defaultdict
+
+
+def dijkstra(n, bus, start, end):
+    costs = [float('inf')] * (n + 1)
+    visited = [False] * (n + 1)
+
+    q = [[0, start, [start]]] # weight, node
+
+    while q:
+        cost, node, path = heapq.heappop(q)
+        if visited[node]:
+            continue
+
+        visited[node] = True
+        costs[node] = cost
+        if node == end:
+            return cost, len(path), path
+
+
+        for next_node, next_cost in bus[node]:
+            total_cost = cost + next_cost
+            if not visited[next_node] and costs[next_node] > total_cost:
+                next_path = path.copy()
+                next_path.append(next_node)
+                heapq.heappush(q, [total_cost, next_node, next_path])
+
+
+n = int(read_line()) # 도시의 개수
+m = int(read_line()) # 버스의 개수
+
+# 버스 정보
+bus =  defaultdict(list)
+for _ in range(m):
+    a, b, c = map(int, read_line().split())
+    bus[a].append((b, c))
+
+a, b = map(int, read_line().split()) # 출발지와 도착지
+
+cost, num_city, path = dijkstra(n, bus, a, b)
+print(cost)
+print(num_city)
+print(*path)