Generate Parentheses
Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.
For example, given n = 3, a solution set is:
[
"((()))",
"(()())",
"(())()",
"()(())",
"()()()"
]
Method
Use DFS method.
Solution
class Solution(object):
def generateParenthesis(self, n):
"""
:type n: int
:rtype: List[str]
"""
res = []
self.dfs('',0,0,n,res)
return res
def dfs(self, s, left, right, n, res):
if len(s) == 2 * n:
res.append(s)
return
if left < n:
self.dfs(s+'(',left+1,right,n, res)
if right < left:
self.dfs(s+')',left,right+1,n, res)
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