From cfbbfd9896cc96379f7374a68ff04b245bb3527c Mon Sep 17 00:00:00 2001 From: Caeden Perelli-Harris Date: Thu, 25 May 2023 11:56:23 +0100 Subject: [PATCH] Merge and add benchmarks to palindrome algorithms in the strings/ directory (#8749) * refactor: Merge and add benchmarks to palindrome * updating DIRECTORY.md * chore: Fix failing tests * Update strings/palindrome.py Co-authored-by: Christian Clauss * Update palindrome.py --------- Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com> Co-authored-by: Christian Clauss --- DIRECTORY.md | 1 - strings/is_palindrome.py | 41 ---------------------------------------- strings/palindrome.py | 40 ++++++++++++++++++++++++++++++++++++++- 3 files changed, 39 insertions(+), 43 deletions(-) delete mode 100644 strings/is_palindrome.py diff --git a/DIRECTORY.md b/DIRECTORY.md index a75723369..fe4baac86 100644 --- a/DIRECTORY.md +++ b/DIRECTORY.md @@ -1156,7 +1156,6 @@ * [Indian Phone Validator](strings/indian_phone_validator.py) * [Is Contains Unique Chars](strings/is_contains_unique_chars.py) * [Is Isogram](strings/is_isogram.py) - * [Is Palindrome](strings/is_palindrome.py) * [Is Pangram](strings/is_pangram.py) * [Is Spain National Id](strings/is_spain_national_id.py) * [Is Srilankan Phone Number](strings/is_srilankan_phone_number.py) diff --git a/strings/is_palindrome.py b/strings/is_palindrome.py deleted file mode 100644 index 406aa2e8d..000000000 --- a/strings/is_palindrome.py +++ /dev/null @@ -1,41 +0,0 @@ -def is_palindrome(s: str) -> bool: - """ - Determine if the string s is a palindrome. - - >>> is_palindrome("A man, A plan, A canal -- Panama!") - True - >>> is_palindrome("Hello") - False - >>> is_palindrome("Able was I ere I saw Elba") - True - >>> is_palindrome("racecar") - True - >>> is_palindrome("Mr. Owl ate my metal worm?") - True - """ - # Since punctuation, capitalization, and spaces are often ignored while checking - # palindromes, we first remove them from our string. - s = "".join(character for character in s.lower() if character.isalnum()) - # return s == s[::-1] the slicing method - # uses extra spaces we can - # better with iteration method. - - end = len(s) // 2 - n = len(s) - - # We need to traverse till half of the length of string - # as we can get access of the i'th last element from - # i'th index. - # eg: [0,1,2,3,4,5] => 4th index can be accessed - # with the help of 1st index (i==n-i-1) - # where n is length of string - - return all(s[i] == s[n - i - 1] for i in range(end)) - - -if __name__ == "__main__": - s = input("Please enter a string to see if it is a palindrome: ") - if is_palindrome(s): - print(f"'{s}' is a palindrome.") - else: - print(f"'{s}' is not a palindrome.") diff --git a/strings/palindrome.py b/strings/palindrome.py index dd1fe316f..bfdb3ddcf 100644 --- a/strings/palindrome.py +++ b/strings/palindrome.py @@ -1,5 +1,7 @@ # Algorithms to determine if a string is palindrome +from timeit import timeit + test_data = { "MALAYALAM": True, "String": False, @@ -33,6 +35,25 @@ def is_palindrome(s: str) -> bool: return True +def is_palindrome_traversal(s: str) -> bool: + """ + Return True if s is a palindrome otherwise return False. + + >>> all(is_palindrome_traversal(key) is value for key, value in test_data.items()) + True + """ + end = len(s) // 2 + n = len(s) + + # We need to traverse till half of the length of string + # as we can get access of the i'th last element from + # i'th index. + # eg: [0,1,2,3,4,5] => 4th index can be accessed + # with the help of 1st index (i==n-i-1) + # where n is length of string + return all(s[i] == s[n - i - 1] for i in range(end)) + + def is_palindrome_recursive(s: str) -> bool: """ Return True if s is a palindrome otherwise return False. @@ -40,7 +61,7 @@ def is_palindrome_recursive(s: str) -> bool: >>> all(is_palindrome_recursive(key) is value for key, value in test_data.items()) True """ - if len(s) <= 1: + if len(s) <= 2: return True if s[0] == s[len(s) - 1]: return is_palindrome_recursive(s[1:-1]) @@ -58,9 +79,26 @@ def is_palindrome_slice(s: str) -> bool: return s == s[::-1] +def benchmark_function(name: str) -> None: + stmt = f"all({name}(key) is value for key, value in test_data.items())" + setup = f"from __main__ import test_data, {name}" + number = 500000 + result = timeit(stmt=stmt, setup=setup, number=number) + print(f"{name:<35} finished {number:,} runs in {result:.5f} seconds") + + if __name__ == "__main__": for key, value in test_data.items(): assert is_palindrome(key) is is_palindrome_recursive(key) assert is_palindrome(key) is is_palindrome_slice(key) print(f"{key:21} {value}") print("a man a plan a canal panama") + + # finished 500,000 runs in 0.46793 seconds + benchmark_function("is_palindrome_slice") + # finished 500,000 runs in 0.85234 seconds + benchmark_function("is_palindrome") + # finished 500,000 runs in 1.32028 seconds + benchmark_function("is_palindrome_recursive") + # finished 500,000 runs in 2.08679 seconds + benchmark_function("is_palindrome_traversal")