《leetcode》longest-consecutive-sequence

题目：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, 3, 4]. Return its length:4.
Your algorithm should run in O(n) complexity.

解析：题目的意思是求最长的连续子序列长度，当然要求时间复杂度为O（n）。

import java.util.Arrays;
public class Solution {
    public int longestConsecutive(int[] num) {
        if(num.length==1){
            return 1;
        }
        int max=0;//最大的长度
        int count=1;//给当前连续的元素计数
        Arrays.sort(num);//先来个排序
        for(int i=1;i<num.length;i++){
            if((num[i]==num[i-1]+1)){//当前的元素是前一个元素+1
                count++;
                if(count>=max){
                    max=count;
                }
            }else if ((num[i]==num[i-1])){//当前的元素和前一个元素一样，不计数
                if(count>=max){
                    max=count;
                }
                continue;
            }
            else{//当前的元素不等于前一个元素，重新计数
                count=1;
                if(count>=max){
                    max=count;
                }
            }
        }
        return max;
    }
}