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#!/usr/bin/env python
# -*- coding: utf-8 -*-
from typing import List
def decode_bits(bits: List[int]) -> List[str]:
"""
Decode a list of binary bits into characters according to the following rules:
[0] -> 'a'
[1, 0] -> 'b'
[1, 1] -> 'c'
Args:
bits: A list of binary bits ending with 0.
Returns:
A list of characters decoded from the binary bits.
"""
decoded = []
i = 0
while i < len(bits):
if bits[i] == 0:
decoded.append('a')
i += 1
elif bits[i] == 1 and bits[i + 1] == 0:
decoded.append('b')
i += 2
elif bits[i] == 1 and bits[i + 1] == 1:
decoded.append('c')
i += 2
return decoded
def is_last_character_a(bits: List[int]) -> int:
"""
Check if the last character decoded from the binary bits is 'a'.
Args:
bits: A list of binary bits ending with 0.
Returns:
1 if the last character decoded is 'a', 0 otherwise.
"""
decoded = decode_bits(bits)
return 1 if decoded[-1] == 'a' else 0
import unittest
class TestDecodeBits(unittest.TestCase):
def test_decode_bits(self):
self.assertEqual(decode_bits([1, 0, 0]), ['b', 'a'])
self.assertEqual(decode_bits([1, 1, 1, 0]), ['c', 'b'])
def test_is_last_character_a(self):
self.assertEqual(is_last_character_a([1, 0, 0]), 1)
self.assertEqual(is_last_character_a([1, 1, 1, 0]), 0)
if __name__ == '__main__':
unittest.main()
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