摘要：
Given a string s containing only digits, return all possible valid IP addresses that can be obtained from s. You can return them in any order. A valid 阅读全文
摘要：
Given an integer array nums of unique elements, return all possible subsets (the power set). The solution set must not contain duplicate subsets. Retu 阅读全文
摘要：
Write a program to solve a Sudoku puzzle by filling the empty cells. A sudoku solution must satisfy all of the following rules: Each of the digits 1-9 阅读全文
摘要：
Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. Example 1: Input: n = 3 Output: ["((()))","(() 阅读全文