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45 lines
1.2 KiB
Python
45 lines
1.2 KiB
Python
# Check whether Graph is Bipartite or Not using BFS
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# A Bipartite Graph is a graph whose vertices can be divided into two independent sets,
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# U and V such that every edge (u, v) either connects a vertex from U to V or a vertex
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# from V to U. In other words, for every edge (u, v), either u belongs to U and v to V,
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# or u belongs to V and v to U. We can also say that there is no edge that connects
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# vertices of same set.
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def checkBipartite(l):
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queue = []
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visited = [False] * len(l)
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color = [-1] * len(l)
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def bfs():
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while queue:
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u = queue.pop(0)
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visited[u] = True
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for neighbour in l[u]:
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if neighbour == u:
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return False
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if color[neighbour] == -1:
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color[neighbour] = 1 - color[u]
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queue.append(neighbour)
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elif color[neighbour] == color[u]:
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return False
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return True
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for i in range(len(l)):
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if not visited[i]:
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queue.append(i)
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color[i] = 0
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if bfs() == False:
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return False
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return True
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# Adjacency List of graph
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l = {0: [1, 3], 1: [0, 2], 2: [1, 3], 3: [0, 2]}
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print(checkBipartite(l))
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