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60 lines
1.6 KiB
Python
60 lines
1.6 KiB
Python
#!/usr/bin/python
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""" Author: OMKAR PATHAK """
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class Graph:
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def __init__(self):
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self.vertices = {}
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def printGraph(self):
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"""prints adjacency list representation of graaph"""
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for i in self.vertices.keys():
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print(i, " : ", " -> ".join([str(j) for j in self.vertices[i]]))
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def addEdge(self, fromVertex, toVertex):
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"""adding the edge between two vertices"""
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if fromVertex in self.vertices.keys():
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self.vertices[fromVertex].append(toVertex)
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else:
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self.vertices[fromVertex] = [toVertex]
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def BFS(self, startVertex):
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# initialize set for storing already visited vertices
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visited = set()
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# create a first in first out queue to store all the vertices for BFS
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queue = []
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# mark the source node as visited and enqueue it
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visited.add(startVertex)
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queue.append(startVertex)
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while queue:
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vertex = queue.pop(0)
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# loop through all adjacent vertex and enqueue it if not yet visited
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for adjacent_vertex in self.vertices[vertex]:
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if adjacent_vertex not in visited:
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queue.append(adjacent_vertex)
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visited.add(adjacent_vertex)
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return visited
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if __name__ == "__main__":
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g = Graph()
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g.addEdge(0, 1)
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g.addEdge(0, 2)
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g.addEdge(1, 2)
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g.addEdge(2, 0)
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g.addEdge(2, 3)
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g.addEdge(3, 3)
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g.printGraph()
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# 0 : 1 -> 2
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# 1 : 2
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# 2 : 0 -> 3
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# 3 : 3
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assert sorted(g.BFS(2)) == [0, 1, 2, 3]
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