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:
"((()))",
"(()())", "(())()", "()(())", "()()()"
class Solution {public:
vector<
string> generateParenthesis(
int n) {
string s;
for(
int i=
0;i<n*
2;i++) s=s+
" ";
vector<
string> result;
int left=n;
int right=n;
gen(result,s,left,right,
0);
return result;
}
void gen(vector<
string>& result,
string& s,
int left,
int right,
int step)
{
if(left>right)
return;
if(left==
0 && right==
0)
{
result.push_back(s);
return;
}
if(left>
0)
{
s[step]=
‘(‘;
gen(result,s,left-
1,right,step+
1);
}
if(right>
0)
{
s[step]=
‘)‘;
gen(result,s,left,right-
1,step+
1);
}
}
};
Generate Parentheses,布布扣,bubuko.com
Generate Parentheses
原文：http://www.cnblogs.com/erictanghu/p/3759285.html
