Leetcode 题目解析之 Generate Parentheses

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:

"((()))", "(()())", "(())()", "()(())", "()()()"

代码语言：javascript复制

    public List<String> generateParenthesis(int n) {
        if (n <= 0) {
            return new ArrayList<String>();
        }
        ArrayList<String> rt = new ArrayList<String>();
        dfs(rt, "", n, n);
        return rt;
    }
    void dfs(ArrayList<String> rt, String s, int left, int right) {
        if (left > right) {
            return;
        }
        if (left == 0 && right == 0) {
            rt.add(s);
        }
        if (left > 0) {
            dfs(rt, s   "(", left - 1, right);
        }
        if (right > 0) {
            dfs(rt, s   ")", left, right - 1);
        }
    }

combinations function parentheses set

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