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33 lines
761 B
Python
33 lines
761 B
Python
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# Kahn's Algorithm is used to find Topological ordering of Directed Acyclic Graph using BFS
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def topologicalSort(l):
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indegree = [0] * len(l)
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queue = []
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topo = []
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cnt = 0
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for key, values in l.items():
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for i in values:
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indegree[i] += 1
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for i in range(len(indegree)):
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if indegree[i] == 0:
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queue.append(i)
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while(queue):
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vertex = queue.pop(0)
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cnt += 1
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topo.append(vertex)
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for x in l[vertex]:
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indegree[x] -= 1
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if indegree[x] == 0:
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queue.append(x)
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if cnt != len(l):
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print("Cycle exists")
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else:
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print(topo)
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# Adjacency List of Graph
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l = {0:[1,2], 1:[3], 2:[3], 3:[4,5], 4:[], 5:[]}
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topologicalSort(l)
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