m Coloring Problem

Author: optimistic-coder-001

Backtracking/mcoloring.py

@@ -0,0 +1,44 @@
+class Graph():
+
+	def __init__(self, vertices):
+		self.V = vertices
+		self.graph = [[0 for column in range(vertices)]\
+							for row in range(vertices)]
+
+	# A utility function to check if the current color assignment
+	# is safe for vertex v
+	def isSafe(self, v, colour, c):
+		for i in range(self.V):
+			if self.graph[v][i] == 1 and colour[i] == c:
+				return False
+		return True
+	
+	# A recursive utility function to solve m
+	# coloring problem
+	def graphColourUtil(self, m, colour, v):
+		if v == self.V:
+			return True
+
+		for c in range(1, m+1):
+			if self.isSafe(v, colour, c) == True:
+				colour[v] = c
+				if self.graphColourUtil(m, colour, v+1) == True:
+					return True
+				colour[v] = 0
+
+	def graphColouring(self, m):
+		colour = [0] * self.V
+		if self.graphColourUtil(m, colour, 0) == False:
+			return False
+
+		# Print the solution
+		print "Solution exist and Following are the assigned colours:"
+		for c in colour:
+			print c,
+		return True
+
+# Driver Code
+g = Graph(4)
+g.graph = [[0,1,1,1], [1,0,1,0], [1,1,0,1], [1,0,1,0]]
+m=3
+g.graphColouring(m)