Google Interview Question: http://www.careercup.com/question?id=4860021380743168

LongestZeroSequenceInBinary.py

import unittest
def LongestZeroSequence(n):
    '''
    Input: n is a string of a binary sequence
    Output: the length of the longest consecutive zero sequence
    when encounter 1, stop counting and save the max sequence so far.
    output the max sequence
    ''' 
    maxSequence = 0       
    seq = 0
    for c in n:
        if (c == '1'):
            if (seq > maxSequence):
                maxSequence = seq
            seq = 0
        else:
            seq += 1
    return maxSequence
    
class Test(unittest.TestCase):
    def test_LongestZeroSequence(self):
        self.assertEqual(LongestZeroSequence("1000010"),4)
        self.assertEqual(LongestZeroSequence("00010000100000100"),5)
        self.assertEqual(LongestZeroSequenceLogn("1000010"),4)

if __name__ == '__main__':
    unittest.main(exit=False)