stack_valid_parentheses.py

"""
link : https://leetcode.com/problems/valid-parentheses/
"""


class Solution:
    def valid_parentheses(s):
        stack = []
        pair = {"(": ")", "{": "}", "[": "]"}
        for e in s:
            if e in ["(", "{", "["]:
                stack.append(e)
            else:
                if stack.pop() != pair[e]:
                    return False

            # if len(stack) == 0:
            #     return True
            # else:
            #     return False
            return True if len(stack) == 0 else False

    # 다른 코드
    def is_valid(s):
        stack = []
        for p in s:
            if p == "(":
                stack.append(")")
            elif p == "[":
                stack.append("]")
            elif p == "{":
                stack.append("}")
            elif not stack or stack.pop() != p:
                return False
        # return not stack 으로 쓰면 1줄로 줄일 수 있음
        return not stack


# TEST
S = Solution()
print(S.is_valid("{({[]})}[]()") is True)
print(S.is_valid("{({[])}[]()") is False)
# print(S.valid_parentheses("{({[]})}[]()"))
# print(S.valid_parentheses("{({[]})}[]()") is True)
# print(S.valid_parentheses("{({[])}[]()") is False)