model_A_answer.py

gistfile1.txt

import ctypes

def to_int32(value):
  """Casts a Python integer to a 32-bit signed integer."""
  return ctypes.c_int32(value).value

def string_hash_py(s):
  """
  Python equivalent of the provided JavaScript stringHash function.

  Args:
    s: The input string.

  Returns:
    The calculated hash as a positive integer.
  """
  hash_val = 0 # Use standard Python arbitrary-precision integer
  for char in s:
    char_code = ord(char) # Get Unicode code point, similar to JS charCodeAt

    # --- Critical part: Simulate JavaScript's bitwise shift behavior ---
    # 1. Convert the current hash_val to a 32-bit signed integer representation
    #    just for the shift operation, like JS does implicitly.
    hash_val_int32 = to_int32(hash_val)

    # 2. Perform the left shift on the 32-bit value.
    #    The result will automatically wrap around if it exceeds 32 bits,
    #    matching the JavaScript behavior for `(hash << 5)`.
    shifted_hash = hash_val_int32 << 5

    # 3. Perform the subtraction and addition using standard Python integers.
    #    Crucially, use the *original* potentially large `hash_val` for the
    #    subtraction, as per the JS formula `(hash << 5) - hash + char`.
    hash_val = shifted_hash - hash_val + char_code
    # --- End of critical part ---

  # Return the absolute value, like JS Math.abs()
  return abs(hash_val)

# --- Test Case ---
input_string = "let's get it started"
result = string_hash_py(input_string)

print(f"Input string: '{input_string}'")
print(f"Python hash result: {result}")

# Verification
expected_result = 7644365391
print(f"Expected result:    {expected_result}")
print(f"Result matches expected: {result == expected_result}")