D. J.:

- Added the leetcode problem and solution for 224 Basic Calculator

Author: nobodyPerfecZ

README.md

@@ -47,6 +47,7 @@ This repository contains awesome LeetCode problems and solutions written in Pyth
 - [202 Happy Number](https://leetcode.com/problems/happy-number/description/)
 - [205 Isomorphic Strings](https://leetcode.com/problems/isomorphic-strings/description/)
 - [219 Contains Duplicates II](https://leetcode.com/problems/contains-duplicate-ii/description/)
+- [224 Basic Calculator](https://leetcode.com/problems/basic-calculator/description/)
 - [228 Summary Ranges](https://leetcode.com/problems/summary-ranges/description/)
 - [242 Valid Anagram](https://leetcode.com/problems/valid-anagram/description/)
 - [290 Word Pattern](https://leetcode.com/problems/word-pattern/description/)

awesome_python_leetcode/_224_basic_calculator.py

@@ -0,0 +1,30 @@
+class Solution:
+    def calculate(self, s: str) -> int:
+        """
+        Given a string s representing a valid expression,
+        implement a basic calculator to evaluate it,
+        and return the result of the evaluation.
+
+        Note: You are not allowed to use any built-in function
+        which evaluates strings as mathematical
+        expressions, such as eval().
+        """
+        stack = []
+        cur, res, sign = 0, 0, 1
+        for c in s:
+            if c.isdigit():
+                cur = cur * 10 + int(c)
+            elif c in ["+", "-"]:
+                res += sign * cur
+                cur = 0
+                sign = 1 if c == "+" else -1
+            elif c == "(":
+                stack.append((res, sign))
+                res, sign = 0, 1
+            elif c == ")":
+                res += sign * cur
+                i_res, i_sign = stack.pop()
+                res *= i_sign
+                res += i_res
+                cur = 0
+        return res + sign * cur

tests/test_224_basic_calculator.py

@@ -0,0 +1,16 @@
+import pytest
+
+from awesome_python_leetcode._224_basic_calculator import Solution
+
+
+@pytest.mark.parametrize(
+    argnames=["s", "expected"],
+    argvalues=[
+        ("1 + 1", 2),
+        (" 2-1 + 2 ", 3),
+        ("(1+(4+5+2)-3)+(6+8)", 23),
+    ],
+)
+def test_func(s: str, expected: int):
+    result = Solution().calculate(s)
+    assert result == expected