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cfbbfd9896
* refactor: Merge and add benchmarks to palindrome
* updating DIRECTORY.md
* chore: Fix failing tests
* Update strings/palindrome.py
Co-authored-by: Christian Clauss <cclauss@me.com>
* Update palindrome.py
---------
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>
105 lines
2.9 KiB
Python
105 lines
2.9 KiB
Python
# Algorithms to determine if a string is palindrome
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from timeit import timeit
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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_traversal(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_traversal(key) is value for key, value in test_data.items())
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True
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"""
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end = len(s) // 2
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n = len(s)
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# We need to traverse till half of the length of string
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# as we can get access of the i'th last element from
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# i'th index.
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# eg: [0,1,2,3,4,5] => 4th index can be accessed
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# with the help of 1st index (i==n-i-1)
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# where n is length of string
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return all(s[i] == s[n - i - 1] for i in range(end))
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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) <= 2:
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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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def benchmark_function(name: str) -> None:
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stmt = f"all({name}(key) is value for key, value in test_data.items())"
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setup = f"from __main__ import test_data, {name}"
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number = 500000
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result = timeit(stmt=stmt, setup=setup, number=number)
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print(f"{name:<35} finished {number:,} runs in {result:.5f} seconds")
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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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# finished 500,000 runs in 0.46793 seconds
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benchmark_function("is_palindrome_slice")
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# finished 500,000 runs in 0.85234 seconds
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benchmark_function("is_palindrome")
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# finished 500,000 runs in 1.32028 seconds
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benchmark_function("is_palindrome_recursive")
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# finished 500,000 runs in 2.08679 seconds
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benchmark_function("is_palindrome_traversal")
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