Fix zero input bug in binary_count_trailing_zeros

TheAlgorithms · satwik-exe · Apr 1, 2026 · Apr 1, 2026 · Apr 1, 2026 · 80bce46523129f7409c1b3f1fc34c25ed4532ca0
commit 80bce46523129f7409c1b3f1fc34c25ed4532ca0
diff --git a/bit_manipulation/binary_count_trailing_zeros.py b/bit_manipulation/binary_count_trailing_zeros.py
@@ -3,8 +3,7 @@
 
 def binary_count_trailing_zeros(a: int) -> int:
     """
-    Take in 1 integer, return a number that is
-    the number of trailing zeros in binary representation of that number.
+    Take in 1 integer, return the number of trailing zeros in binary representation.
 
     >>> binary_count_trailing_zeros(25)
     0
@@ -17,28 +16,39 @@
     >>> binary_count_trailing_zeros(4294967296)
     32
     >>> binary_count_trailing_zeros(0)
-    0
+    Traceback (most recent call last):
+        ...
+    ValueError: Trailing zeros for 0 are undefined
     >>> binary_count_trailing_zeros(-10)
     Traceback (most recent call last):
         ...
     ValueError: Input value must be a positive integer
     >>> binary_count_trailing_zeros(0.8)
     Traceback (most recent call last):
         ...
-    TypeError: Input value must be a 'int' type
+    TypeError: Input value must be an integer
     >>> binary_count_trailing_zeros("0")
     Traceback (most recent call last):
         ...
-    TypeError: '<' not supported between instances of 'str' and 'int'
+    TypeError: Input value must be an integer
     """
+
+    # Type check
+    if not isinstance(a, int):
+        raise TypeError("Input value must be an integer")
+
+    # Edge case: zero
+    if a == 0:
+        raise ValueError("Trailing zeros for 0 are undefined")
+
+    # Negative numbers not allowed
     if a < 0:
         raise ValueError("Input value must be a positive integer")
-    elif isinstance(a, float):
-        raise TypeError("Input value must be a 'int' type")
-    return 0 if (a == 0) else int(log2(a & -a))
+
+    # Core logic
+    return int(log2(a & -a))
 
 
 if __name__ == "__main__":
     import doctest
-
-    doctest.testmod()
+    doctest.testmod()