"""
A brute-force method to calculate status LED color sequences where colors do not repeat consecutively.
ayush@tesseract.in
"""
 
def cartesianProduct(lists):
	'''Returns cartesian product of lists (operands) in the given list of operands)'''
	if lists == []: return [[]]
	return [x + [y] for x in cartesianProduct(lists[:-1]) for y in lists[-1]]
 
def countDuplicateSequences(colorList, sequenceLength):
	'''Prints no. of sequences where entries are non-repeating'''

	count = 0
	i = 0  
	operandList = []

	for i in range(sequenceLength):
		operandList.append(colorList)

	allSequences = cartesianProduct(operandList)  

	for sequence in allSequences:
		for i in range(sequenceLength-1):
			if sequence[i]==sequence[i+1]:
				count += 1
#				print sequence
 
	print 'Total count = ' + str(len(allSequences))            
	print 'Duplicates = ' + str(count)
	print 'Non duplicate count = ' + str(len(allSequences) - count)

countDuplicateSequences(['R','G','B','C','M','Y','W'], 4)