<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 {
    private:
    void solve(string bracket,int countop,int countclosing,string ans,vector<string>& anss,int n){
        if(countop == n and countclosing== n){
            anss.push_back(ans+bracket);
        }
        if(countop <= n){
            solve("(",countop+1,countclosing,ans+bracket,anss,n);
        }
        if(countop > countclosing and countclosing <= n)
            solve(")",countop,countclosing+1,ans+bracket,anss,n);
    }
public:
    vector<string> generateParenthesis(int n) {
        vector<string> anss;
        solve("",0,0,"",anss,n);

        return anss;
    }
};
19386