[Sync Iteration] python/matching-brackets/3

matching-brackets/matching_brackets.py

@@ -28,8 +28,11 @@ def is_paired(input_string: str) -> bool:
     and nested correctly. Any other characters should be ignored. For example,
     "{what is (42)}?" is balanced and "[text}" is not.
 
-    :param input_string:
-    :return:
+    :param input_string: The string to check for balanced brackets
+    :type input_string: str
+    :returns: True if all brackets are properly paired and nested,
+              False otherwise
+    :rtype: bool
     """
     # Empty string
     if not input_string:

solutions/python/matching-brackets/3/matching_brackets.py

@@ -0,0 +1,55 @@
+"""
+Matching Brackets.
+
+You're given the opportunity to write software for the Bracketeer™,
+an ancient but powerful mainframe. The software that runs on it is
+written in a proprietary language. Much of its syntax is familiar,
+but you notice lots of brackets, braces and parentheses. Despite
+the Bracketeer™ being powerful, it lacks flexibility. If the source
+code has any unbalanced brackets, braces or parentheses, the Bracketeer™
+crashes and must be rebooted. To avoid such a scenario, you start writing
+code that can verify that brackets, braces, and parentheses are balanced
+before attempting to run it on the Bracketeer™.
+"""
+
+PAIRS: dict = {
+    "]": "[",
+    "}": "{",
+    ")": "(",
+}
+
+
+def is_paired(input_string: str) -> bool:
+    """
+    Verify that any and all pairs of brackets are matched.
+
+    Given a string containing brackets [], braces {}, parentheses (),
+    or any combination thereof, verify that any and all pairs are matched
+    and nested correctly. Any other characters should be ignored. For example,
+    "{what is (42)}?" is balanced and "[text}" is not.
+
+    :param input_string:
+    :return:
+    """
+    # Empty string
+    if not input_string:
+        return True
+
+    # Remove all non bracket items and convert a string to a list.
+    brackets_list: list[str] = [
+        bracket for bracket in input_string if bracket in "(){}[]"
+    ]
+
+    # Odd number of brackets
+    if len(brackets_list) % 2 != 0:
+        return False
+
+    stack: list[str] = []
+    for bracket in brackets_list:
+        if bracket in "({[":
+            stack.append(bracket)
+        elif bracket in PAIRS:
+            if not stack or stack.pop() != PAIRS[bracket]:
+                return False
+
+    return not stack