37 lines
823 B
Python
37 lines
823 B
Python
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import heapq
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from collections import deque
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from collections import defaultdict
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times = [[2,1,1],[2,3,1],[3,4,1]]
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N = 4
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K = 2
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def networkDelayTime(times, N, K):
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elapsedTime = [0] + [float("inf")] * N
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graph = defaultdict(list)
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heap = [(0, K)]
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# add to adj hash table, where group
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for u, v, w in times:
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graph[u].append((v, w))
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while heap:
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# pop off heap/queue
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time, node = heapq.heappop(heap)
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if time < elapsedTime[node]:
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# process (add to elapsed time array)
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elapsedTime[node] = time
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# add neighbours, include weight
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for v, w in graph[node]:
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heapq.heappush(heap, (time + w, v))
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mx = max(elapsedTime)
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return mx if mx < float("inf") else -1
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print( networkDelayTime(times, N, K) )
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