摘要： 题目： Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set i 阅读全文

摘要： 题目： Given a linked list, remove the nth node from the end of list and return its head. For example, Note:Given n will always be valid.Try to do this i 阅读全文

摘要： 题目： Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique quadruplets in the array 阅读全文