44.py

HSKIM/41to50/44.py

@@ -0,0 +1,39 @@
+from collections import deque
+
+def solution(N, road, K):
+    distance = [float("inf")] * (N + 1)
+    answer = set()
+    graph = {start: {} for start in range(1, N + 1)}    # key: 출발지, value: 도착지와 거리
+    distance[0] = 0
+
+    queue = deque()
+    queue.append([1, 1, 0])
+
+    # value 값에서 더 낮은 거리를 값으로 가지도록 함
+    for start, end, weight in road:
+        if end in graph[start]:
+            graph[start][end] = min(weight, graph[start][end])
+            graph[end][start] = min(weight, graph[start][end])
+        else:
+            graph[start][end] = weight
+            graph[end][start] = weight
+
+    while queue:
+        past, cur, cnt = queue.popleft()
+        answer.add(cur)
+
+        # 이전에 방문한 곳이 아니며 K 값 이내이면서 최단거리일 때 큐에 저장
+        for town in graph[cur]:
+            if town != past and cnt + graph[cur][town] <= K:
+                if cnt + graph[cur][town] < distance[town - 1]:
+                    distance[town - 1] = cnt + graph[cur][town]
+                    queue.append([cur, town, cnt + graph[cur][town]])
+
+
+    return len(answer)
+
+
+N = 5
+road = [[1,2,1],[2,3,3],[5,2,2],[1,4,2],[5,3,1],[5,4,2]]
+K = 3
+print(solution(N, road, K))