717. 1-bit and 2-bit Characters

📋 Đề Bài

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).

Given a binary array bits that ends with 0, return true if the last character must be a one-bit character.

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.

Constraints:

1 <= bits.length <= 1000
bits[i] is either 0 or 1.

💻 Lời Giải

Python 0717-1-bit-and-2-bit-characters.py

class Solution:
    def isOneBitCharacter(self, bits: List[int]) -> bool:
        n = len(bits)
        
        if bits[n - 1] != 0:
            return False
        
        i = 0
        while i < n:
            if i == n - 1:
                return True
            if bits[i] == 1:
                i += 2
            else:
                i += 1
                
        return False