fix: correct doctest examples in binary_parity_pattern function

Author: surlogu

bit_manipulation/binary_parity_pattern.py

@@ -15,17 +15,20 @@ def binary_parity_pattern(number: int) -> str:
     Return a binary parity pattern string for a given integer.
 
     >>> binary_parity_pattern(13)
-    '0b1010'
+    '0b1001'
     >>> binary_parity_pattern(7)
-    '0b111'
+    '0b101'
     >>> binary_parity_pattern(4)
-    '0b10'
+    '0b111'
     >>> binary_parity_pattern(0)
     '0b0'
     """
     if number < 0:
         raise ValueError("Number must be non-negative")
 
+    if number == 0:
+        return "0b0"
+    
     binary_str = bin(number)[2:]
     cum_sum = 0
     pattern = []
@@ -34,11 +37,10 @@ def binary_parity_pattern(number: int) -> str:
         cum_sum += int(bit)
         pattern.append(str(cum_sum % 2))
 
-    result = "0b" + "".join(pattern)
-    return result if result != "0b" else "0b0"
+    result = ''.join(pattern).lstrip('0')
+    return '0b' + (result if result else '0')
 
 
 if __name__ == "__main__":
     import doctest
-
     doctest.testmod()