D. J.:

- Added the leetcode problem and solution for 405

Author: nobodyPerfecZ

README.md

@@ -238,6 +238,7 @@
 - [392 Is Subsequence](https://leetcode.com/problems/is-subsequence/description/)
 - [394 Decode String](https://leetcode.com/problems/decode-string/description/)
 - [399 Evaluate Division](https://leetcode.com/problems/evaluate-division/description/)
+- [405 Convert a Number to Hexadecimal](https://leetcode.com/problems/convert-a-number-to-hexadecimal/description/)
 - [412 Fizz Buzz](https://leetcode.com/problems/fizz-buzz/description/)
 - [415 Add Strings](https://leetcode.com/problems/add-strings/description/)
 - [427 Construct Quad Tree](https://leetcode.com/problems/construct-quad-tree/description/)

awesome_python_leetcode/_405_convert_a_number_to_hexadecimal.py

@@ -0,0 +1,27 @@
+class Solution:
+    """Base class for all LeetCode Problems."""
+
+    def toHex(self, num: int) -> str:
+        """
+        Given a 32-bit integer num, return a string representing its hexadecimal
+        representation. For negative integers, two’s complement method is used.
+
+        All the letters in the answer string should be lowercase characters, and there
+        should not be any leading zeros in the answer except for the zero itself.
+
+        Note: You are not allowed to use any built-in library method to directly solve
+        this problem.
+        """
+        if num == 0:
+            return "0"
+
+        WRAPPER = "0123456789abcdef"
+        MASK = 0xFFFFFFFF
+        num &= MASK
+
+        result = ""
+        while num != 0:
+            bits = num % 16
+            result = WRAPPER[bits] + result
+            num //= 16
+        return result

tests/test_405_convert_a_number_to_hexadecimal.py

@@ -0,0 +1,17 @@
+import pytest
+
+from awesome_python_leetcode._405_convert_a_number_to_hexadecimal import Solution
+
+
+@pytest.mark.parametrize(
+    argnames=["num", "expected"],
+    argvalues=[
+        (26, "1a"),
+        (-1, "ffffffff"),
+        (0, "0"),
+    ],
+)
+def test_func(num: int, expected: str):
+    """Tests the solution of a LeetCode problem."""
+    hex_code = Solution().toHex(num)
+    assert hex_code == expected