docs: add module-level docstring to palindrome algorithms

strings/palindrome.py

@@ -1,4 +1,8 @@
-# Algorithms to determine if a string is palindrome
+"""Algorithms to determine whether a string is a palindrome.
+
+This module provides multiple implementations of palindrome checking
+along with basic benchmarking utilities.
+"""
 
 from timeit import timeit
 
@@ -14,6 +18,7 @@
     "abcdba": False,
     "AB": False,
 }
+
 # Ensure our test data is valid
 assert all((key == key[::-1]) is value for key, value in test_data.items())
 
@@ -25,7 +30,6 @@ def is_palindrome(s: str) -> bool:
     >>> all(is_palindrome(key) is value for key, value in test_data.items())
     True
     """
-
     start_i = 0
     end_i = len(s) - 1
     while start_i < end_i:
@@ -47,12 +51,6 @@ def is_palindrome_traversal(s: str) -> bool:
     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))
 
 
@@ -65,10 +63,9 @@ def is_palindrome_recursive(s: str) -> bool:
     """
     if len(s) <= 1:
         return True
-    if s[0] == s[len(s) - 1]:
+    if s[0] == s[-1]:
         return is_palindrome_recursive(s[1:-1])
-    else:
-        return False
+    return False
 
 
 def is_palindrome_slice(s: str) -> bool:
@@ -84,7 +81,7 @@ def is_palindrome_slice(s: str) -> bool:
 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
+    number = 500_000
     result = timeit(stmt=stmt, setup=setup, number=number)
     print(f"{name:<35} finished {number:,} runs in {result:.5f} seconds")
 
@@ -94,13 +91,8 @@ def benchmark_function(name: str) -> None:
         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")