서강그라운드 풀이

Author: saebyeok0306

BAEKJOON/3Gold/서강그라운드.py

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+# 그래프 이론, 데이크스트라, 최단 경로, 플로이드–워셜
+# https://www.acmicpc.net/problem/14938
+
+# 두 지역 간에 더 짧은 경로가 있을 수 있음.
+# 
+
+def dijkstra(items, graph, M, start):
+    import heapq
+    
+    INF = 0xFFFFFFFF
+    dist = [INF for _ in range(N+1)]
+    dist[start] = 0
+    heap = [(0, start)]
+
+    while heap:
+        cost, node = heapq.heappop(heap)
+        if cost > dist[node]: continue
+
+        for _node, _cost in graph[node]:
+            sum_cost = dist[node] + _cost
+            if sum_cost >= dist[_node]: continue
+            if sum_cost > M: continue
+            dist[_node] = sum_cost
+            heapq.heappush(heap, (sum_cost, _node))
+    
+    total_item = 0
+    for i in range(1, N+1):
+        if dist[i] != INF:
+            total_item += items[i]
+    return total_item
+
+if __name__ == "__main__":
+    from collections import defaultdict
+    input = __import__("sys").stdin.readline
+
+    N,M,R = map(int, input().split())
+    items = [None] + list(map(int, input().split()))
+    graph = defaultdict(list)
+    for _ in range(R):
+        a,b,l = map(int, input().split())
+        graph[a].append((b,l))
+        graph[b].append((a,l))
+    
+    max_item = 0
+    for n in range(1, N+1):
+        item = dijkstra(items, graph, M, n)
+        if max_item < item:
+            max_item = item
+    
+    print(max_item)