mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-12-18 09:10:16 +00:00
44 lines
1.2 KiB
Python
44 lines
1.2 KiB
Python
|
# Check whether Graph is Bipartite or Not using BFS
|
||
|
|
|
||
|
|
# A Bipartite Graph is a graph whose vertices can be divided into two independent sets,
|
||
|
|
# U and V such that every edge (u, v) either connects a vertex from U to V or a vertex
|
||
|
|
# from V to U. In other words, for every edge (u, v), either u belongs to U and v to V,
|
||
|
|
# or u belongs to V and v to U. We can also say that there is no edge that connects
|
||
|
|
# vertices of same set.
|
||
|
|
def checkBipartite(l):
|
||
|
|
queue = []
|
||
|
|
visited = [False] * len(l)
|
||
|
|
color = [-1] * len(l)
|
||
|
|
|
||
|
|
def bfs():
|
||
|
|
while(queue):
|
||
|
|
u = queue.pop(0)
|
||
|
|
visited[u] = True
|
||
|
|
|
||
|
|
for neighbour in l[u]:
|
||
|
|
|
||
|
|
if neighbour == u:
|
||
|
|
return False
|
||
|
|
|
||
|
|
if color[neighbour] == -1:
|
||
|
|
color[neighbour] = 1 - color[u]
|
||
|
|
queue.append(neighbour)
|
||
|
|
|
||
|
|
elif color[neighbour] == color[u]:
|
||
|
|
return False
|
||
|
|
|
||
|
|
return True
|
||
|
|
|
||
|
|
for i in range(len(l)):
|
||
|
|
if not visited[i]:
|
||
|
|
queue.append(i)
|
||
|
|
color[i] = 0
|
||
|
|
if bfs() == False:
|
||
|
|
return False
|
||
|
|
|
||
|
|
return True
|
||
|
|
|
||
|
|
# Adjacency List of graph
|
||
|
|
l = {0:[1,3], 1:[0,2], 2:[1,3], 3:[0,2]}
|
||
|
|
print(checkBipartite(l))
|