Merge pull request #10 from codewithme-py/feat/reverse-integer-0007

problem solution & test 0007

Author: codewithme-py

solutions/reverse_integer_0007.py

@@ -0,0 +1,29 @@
+class Solution:
+    def reverse(self, x: int) -> int:
+        """
+        Reverse digits of an integer.
+        Example 1:
+        Input: x = 123
+        Output: 321
+        Example 2:
+        Input: x = -123
+        Output: -321
+        Example 3:
+        Input: x = 120
+        Output: 21
+        Note:
+        Assume we are dealing with an environment which could only store
+        integers within the 32-bit signed integer range: [−2^31,  2^31 − 1].
+        For the purpose of this problem, assume that
+        your function returns 0 when the reversed integer overflows.
+        """
+        int_min, int_max, reversed_num = -2**31, 2**31 - 1, 0
+        sign = 1 if x >= 0 else -1
+        x_abs = abs(x)
+        while x_abs:
+            digit = x_abs % 10
+            reversed_num = reversed_num * 10 + digit
+            if sign * reversed_num < int_min or sign * reversed_num > int_max:
+                return 0
+            x_abs //= 10
+        return sign * reversed_num

tests/test_reverse_integer_0007.py

@@ -0,0 +1,19 @@
+import pytest
+
+from solutions.reverse_integer_0007 import Solution
+
+
+@pytest.mark.parametrize('args, expected', [
+    (123, 321),
+    (-123, -321),
+    (120, 21),
+    (0, 0),
+    (1534236469, 0),
+    (-2147483648, 0),
+    (1563847412, 0),
+    (1463847412, 2147483641),
+    (1463847412, 2147483641),
+])
+def test_solution(args, expected):
+    sol = Solution()
+    assert sol.reverse(args) == expected