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  1. class Solution:
  2.     def reverse(self, x: int) -> int:
  3.         # Limites de 32-bit signed integer
  4.         INT_MAX = 2**31 - 1  # 2147483647
  5.         INT_MIN = -2**31     # -2147483648
  6.  
  7.         # Guardar o sinal e trabalhar com valor absoluto
  8.         sign = -1 if x < 0 else 1
  9.         x = abs(x)
  10.  
  11.         # Reverter o número
  12.         result = 0
  13.         while x != 0:
  14.             digit = x % 10
  15.             x //= 10
  16.  
  17.             # Verificar overflow ANTES de adicionar o dígito
  18.             # Se result > INT_MAX // 10, então result * 10 causaria overflow
  19.             if result > INT_MAX // 10:
  20.                 return 0
  21.  
  22.             # Se result == INT_MAX // 10, precisamos verificar o dígito
  23.             # Para INT_MAX = 2147483647, INT_MAX // 10 = 214748364
  24.             # Se estamos neste valor e o próximo dígito > 7, teremos overflow
  25.             if result == INT_MAX // 10:
  26.                 # Para números positivos: verificar se dígito > 7
  27.                 # Para números negativos: verificar se dígito > 8
  28.                 if (sign == 1 and digit > 7) or (sign == -1 and digit > 8):
  29.                     return 0
  30.  
  31.             result = result * 10 + digit
  32.  
  33.         return sign * result
  34.  
  35.  
  36. # Testes
  37. def test_solution():
  38.     sol = Solution()
  39.  
  40.     # Casos do exemplo
  41.     print(f"reverse(123) = {sol.reverse(123)}")  # Expected: 321
  42.     print(f"reverse(-123) = {sol.reverse(-123)}")  # Expected: -321
  43.     print(f"reverse(120) = {sol.reverse(120)}")  # Expected: 21
  44.  
  45.     # Casos extremos
  46.     print(f"reverse(0) = {sol.reverse(0)}")  # Expected: 0
  47.     print(f"reverse(1534236469) = {sol.reverse(1534236469)}")  # Expected: 0 (overflow)
  48.     print(f"reverse(-2147483648) = {sol.reverse(-2147483648)}")  # Expected: 0 (overflow)
  49.     print(f"reverse(2147483647) = {sol.reverse(2147483647)}")  # Expected: 0 (overflow)
  50.  
  51.     # Outros casos
  52.     print(f"reverse(1000) = {sol.reverse(1000)}")  # Expected: 1
  53.     print(f"reverse(-1000) = {sol.reverse(-1000)}")  # Expected: -1
  54.  
  55.  
  56. if __name__ == "__main__":
  57.     test_solution()
Success #stdin #stdout 0.09s 14156KB
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stdin
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Standard input is empty
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reverse(123) = 321
reverse(-123) = -321
reverse(120) = 21
reverse(0) = 0
reverse(1534236469) = 0
reverse(-2147483648) = 0
reverse(2147483647) = 0
reverse(1000) = 1
reverse(-1000) = -1
https://ideone.com/WKcQFC
language:
Python 3 (python  3.12)
created:
6 days ago
visibility:
public

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