From ce2f61c7719bf994327ecf0cc7325667731f14dc Mon Sep 17 00:00:00 2001
From: wazedkhan <wazedkhan119399@gmail.com>
Date: Sun, 22 Feb 2026 23:39:14 +0600
Subject: [PATCH] prac: valid parentheses mapping solution reasoning

---
 .../best_time_buy_sell_stock_121.py           | 22 +++++++-------
 LeetCode/easy/valid_parentheses_20.py         | 12 ++++++++
 tests/test_leetcode.py                        | 23 --------------
 tests/test_leetcode_easy.py                   | 30 ++++++++++++++++++-
 4 files changed, 51 insertions(+), 36 deletions(-)
 rename LeetCode/{easy => dump}/best_time_buy_sell_stock_121.py (94%)
 create mode 100644 LeetCode/easy/valid_parentheses_20.py

diff --git a/LeetCode/easy/best_time_buy_sell_stock_121.py b/LeetCode/dump/best_time_buy_sell_stock_121.py
similarity index 94%
rename from LeetCode/easy/best_time_buy_sell_stock_121.py
rename to LeetCode/dump/best_time_buy_sell_stock_121.py
index 38a091d..69773a5 100644
--- a/LeetCode/easy/best_time_buy_sell_stock_121.py
+++ b/LeetCode/dump/best_time_buy_sell_stock_121.py
@@ -3,7 +3,7 @@
 
 class Solution:
     """
-    
+
     price = [7,6,4,3,1]
     price = [7,1,5,3,6,4]
     price_3 = [2,7,1,5,4]
@@ -30,7 +30,7 @@ class Solution:
     update()
         if min_price > price then min_price = price
         if price - min_price > best_profit best_profit = min_price - price
-    
+
     update
     Day 0: price is 7 and min_price is 7 best_profit is 0
     update
@@ -51,33 +51,31 @@ class Solution:
         Boom! At the end, we return that
 
     """
+
     def bruteForceMaxProfit(self, prices: List[int]) -> int:
         best_profit = 0
         for i in range(len(prices)):
             for j in range(i + 1, len(prices)):
                 profit = prices[j] - prices[i]
-                
+
                 best_profit = max(best_profit, profit)
-        
+
         return best_profit
-    
+
     def maxProfit(self, prices: List[int]) -> int:
-        min_price = float('inf')
+        min_price = float("inf")
         best_profit = 0
 
         for price in prices:
             if price < min_price:
                 min_price = price
-            
+
             if price - min_price > best_profit:
                 best_profit = price - min_price
 
         return best_profit
 
 
-
-
-
-price_3 = [7,6,4,3,1]
+price_3 = [7, 6, 4, 3, 1]
 sol = Solution().maxProfit(price_3)
-print(f"Best profit: {sol}")
\ No newline at end of file
+print(f"Best profit: {sol}")
diff --git a/LeetCode/easy/valid_parentheses_20.py b/LeetCode/easy/valid_parentheses_20.py
new file mode 100644
index 0000000..281f8e6
--- /dev/null
+++ b/LeetCode/easy/valid_parentheses_20.py
@@ -0,0 +1,12 @@
+class Solution:
+    def isValidByMapping(self, s: str) -> bool:
+        stack = []
+        mapping = {"}": "{", ")": "(", "]": "["}
+
+        for p in s:
+            if stack and p in mapping and stack[-1] == mapping[p]:
+                stack.pop()
+            else:
+                stack.append(p)
+
+        return len(stack) == 0
diff --git a/tests/test_leetcode.py b/tests/test_leetcode.py
index 8ec6cb1..09ecf04 100644
--- a/tests/test_leetcode.py
+++ b/tests/test_leetcode.py
@@ -248,29 +248,6 @@ def test_reverse_integer(x: int, expected: int):
     assert result == expected
 
 
-@pytest.mark.parametrize(
-    "s, expected",
-    [
-        ("()", True),  # Single pair
-        ("()[]{}", True),  # Multiple valid pairs
-        ("(]", False),  # Mismatched parentheses
-        ("([)]", False),  # Nested but invalid
-        ("{[]}", True),  # Properly nested
-        ("", True),  # Empty string
-        ("(", False),  # Single opening parenthesis
-        (")", False),  # Single closing parenthesis
-        ("(((((((((())))))))))", True),  # Deeply nested
-        ("(((((((((()))", False),  # Deeply nested but incomplete
-    ],
-)
-def test_is_valid_parentheses(s: str, expected: bool):
-    from LeetCode.valid_parentheses_20 import Solution
-
-    solution = Solution()
-    result = solution.isValid(s)
-    assert result == expected
-
-
 @pytest.mark.parametrize(
     "s, expected",
     [
diff --git a/tests/test_leetcode_easy.py b/tests/test_leetcode_easy.py
index df9be14..697b45f 100644
--- a/tests/test_leetcode_easy.py
+++ b/tests/test_leetcode_easy.py
@@ -85,7 +85,7 @@ def test_generate(numRows, expected):
     ],
 )
 def test_max_profit(prices, expected):
-    from LeetCode.easy.best_time_buy_sell_stock_121 import Solution
+    from LeetCode.dump.best_time_buy_sell_stock_121 import Solution
 
     solution = Solution()
     assert solution.maxProfit(prices) == expected
@@ -182,3 +182,31 @@ def test_missing_number(nums, expected):
 
     solution = Solution()
     assert solution.missingNumber(nums) == expected
+
+
+@pytest.mark.parametrize(
+    "s, expected",
+    [
+        ("()", True),  # Single pair
+        ("()[]{}", True),  # Multiple valid pairs
+        ("(]", False),  # Mismatched parentheses
+        ("([)]", False),  # Nested but invalid
+        ("{[]}", True),  # Properly nested
+        ("", True),  # Empty string
+        ("(", False),  # Single opening parenthesis
+        (")", False),  # Single closing parenthesis
+        ("(((((((((())))))))))", True),  # Deeply nested
+        ("(((((((((()))", False),  # Deeply nested but incomplete
+    ],
+)
+def test_is_valid_parentheses(s: str, expected: bool):
+    from LeetCode.easy.valid_parentheses_20 import Solution as Sol
+    from LeetCode.valid_parentheses_20 import Solution
+
+    solution = Solution()
+    result = solution.isValid(s)
+    assert result == expected
+
+    sol = Sol()
+    res = sol.isValidByMapping(s)
+    assert res == expected