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LeetCode solutions

1197. Parsing A Boolean Expression

My accepted Python solution to LeetCode problem 1197, Parsing A Boolean Expression, running in 14ms.

  • Difficulty: Hard
  • Python
  • Runtime 14ms
  • Memory 17.5MB

Read the problem on LeetCode View on GitHub

The problem statement is LeetCode’s and stays on their site. What follows is my accepted solution.

Python

Accepted on LeetCode — runtime 14ms, memory 17.5MB, accepted 2025-12-29.

python
class Solution:
    def parseBoolExpr(self, expression: str) -> bool:
        stack = []
        
        for char in expression:
            if char == ',' or char == '(':
                continue
            elif char == 't':
                stack.append(True)
            elif char == 'f':
                stack.append(False)
            elif char in '!&|':
                stack.append(char)
            elif char == ')':
                # Collect all boolean values until we hit the operator
                values = []
                while stack and stack[-1] not in ['!', '&', '|']:
                    values.append(stack.pop())
                if stack:
                    op = stack.pop()
                    if op == '!':
                        stack.append(not values[0])
                    elif op == '&':
                        stack.append(all(values))
                    else:  # op == '|'
                        stack.append(any(values))
        
        return stack[0]

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