# Link: https://leetcode.com/problems/valid-parentheses/description/


class Solution:
    def isValid(self, s: str) -> bool:
        c = []  # Checker stack
        m = {
            ")": "(",
            "}": "{",
            "]": "[",
        }
        cb = m.keys()
        op = m.values()
        for char in s:
            if len(c) == 0:
                c.append(char)
                continue
            if char in op:
                c.append(char)
                continue
            if char in cb:
                if len(c) > 0 and c[-1] == m[char]:
                    c.pop()
                    continue
                if len(c) > 0 and c[-1] != m[char]:
                    return False
                if len(c) == 0:
                    return False
        print(f"c = {c} (len={len(c)})")
        return False if len(c) > 0 else True


if __name__ == "__main__":
    tt = "()[]{}"
    sol = Solution
    print(f"Initial: {tt}")
    print(sol().isValid(tt))
    print("-" * 60)
    tt = "()"
    print(f"Initial: {tt}")
    print(sol().isValid(tt))
    print("-" * 60)
    tt = "())"
    print(f"Initial: {tt}")
    print(sol().isValid(tt))
    print("-" * 60)
    tt = "([])"
    print(f"Initial: {tt}")
    print(sol().isValid(tt))
    print("-" * 60)
    tt = "("
    print(f"Initial: {tt}")
    print(sol().isValid(tt))
    print("-" * 60)
    tt = "(])"
    print(f"Initial: {tt}")
    print(sol().isValid(tt))
    print("-" * 60)