Rebeca Muniz #Cedar

graphs/possible_bipartition.py

@@ -1,12 +1,56 @@
 # Can be used for BFS
 from collections import deque 
+class Graph():
 
-def possible_bipartition(dislikes):
+ def __init__(self, V):
+ self.V = V
+ self.graph = [[0 for column in range(V)] \
+ for row in range(V)]
+
+def possible_bipartition(self, dislikes):
  """ Will return True or False if the given graph
  can be bipartitioned without neighboring nodes put
  into the same partition.
- Time Complexity: ?
- Space Complexity: ?
+ Time Complexity: O(N+E)
+ Space Complexity: O(N)
  """
- pass
-
+ colorArr = [-1] * self.V
+
+ # Assign first color to source
+ colorArr[dislikes] = 1
+
+ # Create a queue (FIFO) of vertex numbers and
+ # enqueue source vertex for BFS traversal
+ queue = []
+ queue.append(dislikes)
+
+ # Run while there are vertices in queue
+ # (Similar to BFS)
+ while queue:
+
+ u = queue.pop()
+
+ # Return false if there is a self-loop
+ if self.graph[u][u] == 1:
+ return False;
+
+ for v in range(self.V):
+
+ # An edge from u to v exists and destination
+ # v is not colored
+ if self.graph[u][v] == 1 and colorArr[v] == -1:
+
+ # Assign alternate color to this
+ # adjacent v of u
+ colorArr[v] = 1 - colorArr[u]
+ queue.append(v)
+
+ # An edge from u to v exists and destination
+ # v is colored with same color as u
+ elif self.graph[u][v] == 1 and colorArr[v] == colorArr[u]:
+ return False
+
+ # If we reach here, then all adjacent
+ # vertices can be colored with alternate
+ # color
+ return True