# 有效的括号

给定一个只包括 '('')''{''}''['']' 的字符串 s ,判断字符串是否有效。

有效字符串需满足:

  1. 左括号必须用相同类型的右括号闭合。
  2. 左括号必须以正确的顺序闭合。

 

示例 1:

输入:s = "()"
输出:
true

示例 2:

输入:s = "()[]{}"
输出:
true

示例 3:

输入:s = "(]"
输出:
false

示例 4:

输入:s = "([)]"
输出:
false

示例 5:

输入:s = "{[]}"
输出:
true

 

提示:

## template ```python class Solution: def isValid(self, s: str) -> bool: parentheses = [ '(', '[', '{', ')', ']', '}' ] i = 0 sum = [0, 0, 0] top = [] while i < len(s): c = s[i] j = 0 while j <= 2: if c == parentheses[j]: top.append(j) sum[j] += 1 elif c == parentheses[j+3]: if len(top) == 0 or top[len(top)-1] != j: return False top.pop() sum[j] -= 1 j += 1 i += 1 if sum[0] != 0 or sum[1] != 0 or sum[2] != 0: return False else: return True # %% s = Solution() print(s.isValid(s = "()[]{}")) ``` ## 答案 ```python ``` ## 选项 ### A ```python ``` ### B ```python ``` ### C ```python ```