摘要：
A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.
Return a deep copy of the list. 阅读全文
摘要：
Given an array of integers, every element appears three times except for one. Find that single one. 阅读全文
摘要：
Given an array of integers, every element appears twice except for one. Find that single one. 阅读全文
摘要：
There are N children standing in a line. Each child is assigned a rating value. 阅读全文
摘要：
There are N gas stations along a circular route, where the amount of gas at station i is gas[i]. 阅读全文