给定一个括号序列,写一个函数用于生成正确形式的括号组合。
例如,给定 n = 3,一个解决方案集是:
"((()))", "(()())", "(())()", "()(())", "()()()"
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> result; vector<string> generateParenthesis(int n) { generate(0, 0, "", n); return result; } void generate(int left, int right, string s, int n) { if(right == n) { result.push_back(s); } else { if(left < n) { generate(left + 1, right, s + "(", n); } if(right < left) { generate(left, right + 1, s + ")", n); } } } };
我自己写的是用排列组合加上第 20 题的代码,有些繁琐不如上面的解法,为了更直观的理解这个递归的过程,就画了下面这个示意图。轻拍……