solve.cpp

#include <string>
#include <vector>
#include <algorithm>
#include <iostream>
using namespace std;
class Solution {
	public:
		vector<string> generateParenthesis(int n) {
			vector<string> result;
			if (n < 1)
				return result;
			generate(result, "", 0, n);
			return result;
		}
		void generate(vector<string> &result, string value, int open, int n) {
			if (n == 0) {
				for (int i = 0; i < open; ++i)
					value += ')';
				result.push_back(value);
				return;
			}
			if (open == 0) {
				generate(result, value + '(', 1, n - 1);
			} else {
				generate(result, value + ')', open - 1, n);
				generate(result, value + '(', open + 1, n - 1);
			}
		}
};
int main(int argc, char **argv)
{
	Solution solution;
	auto result = solution.generateParenthesis(10);
	for_each(result.begin(), result.end(), [](string s){cout << s << endl;});
}