括号生成实现

Posted 2021-05-20 今夜无风

 

问题：

# 数字 n 代表生成括号的对数，请你设计一个函数，用于能够生成所有可能的并且 有效的 括号组合。 
# 
#  
# 
#  示例 1： 
# 
#  
# 输入：n = 3
# 输出：["((()))","(()())","(())()","()(())","()()()"]

实现：

# leetcode submit region begin(Prohibit modification and deletion)
class Solution:
    def generateParenthesis(self, n: int) -> List[str]:
        res = []
        def _recursion(res, n, left, right, s):
            if len(s) == 2 * n:
                res.append(s)
                return
            if left < n:
                _recursion(res, n, left + 1, right, s + \'(\')
            if left > right:
                _recursion(res, n, left, right + 1, s + \')\')
        _recursion(res, n, 0, 0, \'\')
        return res
# leetcode submit region end(Prohibit modification and deletion)