Valid Parentheses

/***
9.6
Implement an algorithm to prink all valid (eg. properly opened and closed combinations of n-pairs of parentheses)
EXAMPLE:
input: 3
Output: ()()(), ((())), ()(()), (()()), (())()
***/

#include<iostream>
#include<set>
#include <string>

using namespace std;

void validParentheses(int n, set<string> *prt) {
       if(n==0) return;

       if (prt->empty())
       {
              string s;
              s.push_back('(');
              s.push_back(')');
              prt->insert(s);
       } else {
              set<string> ts;
              set<string> :: iterator it;
              ts = *prt;
              prt->clear();

              for(it = ts.begin(); it != ts.end(); it++) {
                     string s = *it;
                     string :: iterator it1, it2;
                     for(int i=0; i<s.size(); i++) {
                           if(s[i] == '(') {
                                  s.insert(i, "(");
                                  string temp = s;
                                  for(int j=i+1; j<s.size(); j++) {
                                         if(temp[j] == ')') {
                                                temp = s;
                                                temp.insert(j+1, ")");
                                                prt->insert(temp);
                                         }            
                                  }
                           }
                           s = *it;
                     }
                     s.push_back('(');
                     s.push_back(')');
                     prt->insert(s);
              }
       }
       validParentheses(n-1, prt);
}

void main() {
       int n = 3;

       set<string> partset;
       set<string> :: iterator it;

       validParentheses(n, &partset);
       for (it = partset.begin(); it != partset.end(); it++)
       {
              cout<<*it<<endl;
       }

}

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