摘要：
Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate number must exist. 阅读全文
摘要：
Given a linked list, return the node where the cycle begins. If there is no cycle, return null. 题意：找一个链表中是否含有环，如果没有则返回null，如果有则返回环的起点 我的解法，投机取巧了，我改了va 阅读全文
摘要：
S and T are strings composed of lowercase letters. In S, no letter occurs more than once. S was sorted in some custom order previously. We want to per 阅读全文