717. 1-bit and 2-bit Characters

1. Question

https://leetcode.com/problems/1-bit-and-2-bit-characters/

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

2. Solution:

class Solution:
def dfs(self, bits):
size = len(bits)

if size == 1:
return True

if size == 2:
if bits[0] == 1:
return False
else:
return True

if size >= 3:
if bits[0] == 1:
return self.dfs(bits[2:])
else:
return self.dfs(bits[1:])

def isOneBitCharacter(self, bits):
"""
:type bits: List[int]
:rtype: bool
"""
return self.dfs(bits)