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99a42f2b58
* Move files to strings-folder * moved the file "words" back to the original folder * moved "anagram.py" also back * fix the codespell ignore-list
67 lines
1.6 KiB
Python
67 lines
1.6 KiB
Python
# Algorithms to determine if a string is palindrome
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test_data = {
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"MALAYALAM": True,
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"String": False,
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"rotor": True,
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"level": True,
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"A": True,
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"BB": True,
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"ABC": False,
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"amanaplanacanalpanama": True, # "a man a plan a canal panama"
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}
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# Ensure our test data is valid
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assert all((key == key[::-1]) is value for key, value in test_data.items())
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def is_palindrome(s: str) -> bool:
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"""
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Return True if s is a palindrome otherwise return False.
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>>> all(is_palindrome(key) is value for key, value in test_data.items())
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True
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"""
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start_i = 0
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end_i = len(s) - 1
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while start_i < end_i:
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if s[start_i] == s[end_i]:
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start_i += 1
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end_i -= 1
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else:
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return False
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return True
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def is_palindrome_recursive(s: str) -> bool:
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"""
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Return True if s is a palindrome otherwise return False.
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>>> all(is_palindrome_recursive(key) is value for key, value in test_data.items())
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True
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"""
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if len(s) <= 1:
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return True
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if s[0] == s[len(s) - 1]:
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return is_palindrome_recursive(s[1:-1])
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else:
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return False
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def is_palindrome_slice(s: str) -> bool:
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"""
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Return True if s is a palindrome otherwise return False.
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>>> all(is_palindrome_slice(key) is value for key, value in test_data.items())
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True
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"""
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return s == s[::-1]
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if __name__ == "__main__":
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for key, value in test_data.items():
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assert is_palindrome(key) is is_palindrome_recursive(key)
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assert is_palindrome(key) is is_palindrome_slice(key)
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print(f"{key:21} {value}")
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print("a man a plan a canal panama")
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