题目：

题解：

var res []stringfunc generateParenthesis(n int) []string {res = make([]string, 0)dfs(n, 0, 0, "")return res
}func dfs(n int, lc int, rc int, path string) {if lc == n && rc == n {res = append(res, path)return } else {if lc < n {dfs(n, lc + 1, rc, path + "(")} if rc < lc {dfs(n, lc, rc + 1, path + ")")}}}