<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 {
    vector<string> result;
    string str;
    void generate(int open, int n, char* c)
    {
        if (*c == '\0') {
            result.push_back(str);
            return;
        }
 
        if (open > 0) {
            *c = ')';
            generate(open - 1, n, c + 1);
        }
        if (n > 0) {
            *c = '(';
            generate(open + 1, n - 1, c + 1);
        }
    }
public:
    vector<string> generateParenthesis(int n) {
        str.assign(2 * n, ' ');
        generate(0, n, str.data());
        return result;
    }
};
9059