<p>Given <code>n</code> pairs of parentheses, write a function to <em>generate all combinations of well-formed parentheses</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> n = 3
<strong>Output:</strong> ["((()))","(()())","(())()","()(())","()()()"]
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> n = 1
<strong>Output:</strong> ["()"]
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= n &lt;= 8</code></li>
</ul>

class Solution:
    def generateParenthesis(self, n: int) -> List[str]:
        ans = []
        def backtrack(curr,open,close):
            if len(curr) == 2*n:
                if open == close:
                    ans.append("".join(curr))
            
            if open < n:
                curr.append("(")
                backtrack(curr,open+1,close)
                curr.pop()
            if close < open:
                curr.append(")")
                backtrack(curr,open,close+1)
                curr.pop()
        backtrack([],0,0)
        return ans
16600