qq_37558635的博客

1. Divide And Conquer /** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode() {} * ListNode(int val) { this.val = val; } * ListNode(int val, ListNode next) { this.val = val; thi

1. brute force class Solution { // using the features of char array public List<String> generateParenthesis(int n) { List<String> combinations = new ArrayList(); // n pairs, the length of each combination is 2 * n