isOneBitCharacter.py

# -*- coding: utf-8 -*-
'''
We have two special characters. The first character can be represented by one bit 0. The second character can be represented by two bits (10 or 11).

Now given a string represented by several bits. Return whether the last character must be a one-bit character or not. The given string will always end with a zero.

Example 1:
Input: 
bits = [1, 0, 0]
Output: True
Explanation: 
The only way to decode it is two-bit character and one-bit character. So the last character is one-bit character.
Example 2:
Input: 
bits = [1, 1, 1, 0]
Output: False
Explanation: 
The only way to decode it is two-bit character and two-bit character. So the last character is NOT one-bit character.
Note:

1 <= len(bits) <= 1000.
bits[i] is always 0 or 1.
'''
"""
        :type bits: List[int]
        :rtype: bool
        """
class Solution(object):
    def isOneBitCharacter(self, bits):
        if len(bits) == 1:
            return True
        elif (bits[-2]) == 0:
            return True
        else:
            i ,prev = 0,0
            while i < len(bits):
                prev = i
                if bits[i] == 1:
                    i += 2
                else:
                    i += 1
            return True if i == prev + 1 else False

if __name__ == "__main__":
	sol = Solution()
	bits = [1,1,0,1,1,1,0,1,1,1,0,0,0]
	print(sol.isOneBitCharacter(bits))