33 lines
738 B
Python
33 lines
738 B
Python
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import collections
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n = 3
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edges = [[0,1,100],[1,2,200],[0,2,500]]
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src = 0
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dst = 2
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k = 1
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def findCheapestPrice(n, flights, src, dst, K):
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if src == dst: return 0
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d, seen = collections.defaultdict(list), collections.defaultdict(lambda: float('inf'))
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for u, v, p in flights:
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d[u] += [(v, p)]
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q = [(src, -1, 0)]
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while q:
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pos, k, cost = q.pop(0)
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if pos == dst or k == K: continue
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for nei, p in d[pos]:
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if cost + p >= seen[nei]:
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continue
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else:
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seen[nei] = cost+p
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q += [(nei, k+1, cost+p)]
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return seen[dst] if seen[dst] < float('inf') else -1
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print( findCheapestPrice(n, edges, src, dst, k) )
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