Given an unsorted array of integers, find the length of the longest consecutive elements sequence.For example,Given [100, 4, 200, 1, 3, 2],The longest consecutive elements sequence is [1, 2,

转：http://www.cnblogs.com/hiddenfox/p/3408931.html题目要求Linked List CycleGiven a linked list, determine if it has a cycle in it.Follow up: Can you solve it without using extra space?如