Longest Consecutive Sequence

总结帖 http://blog.csdn.net/linhuanmars/article/details/39366817

code 参考帖 http://www.cnblogs.com/springfor/p/3869981.html

http://blog.csdn.net/linhuanmars/article/details/22964467

逻辑上很清晰，iterator的用法get

 public int longestConsecutive(int[] num) {

        if(num==null|| num.length==0) return 0;

        int  res = 1;

        HashSet<Integer> hs = new HashSet<Integer>();

        for(int i=0; i<num.length; i++){

            hs.add(num[i]);

        }

         

        while(!hs.isEmpty()){

            Iterator it  = hs.iterator();

            int item = (Integer) it.next();

            //dont forget this

            hs.remove(item);

            int cnt = 1;

            int less = item-1;

            int more = item+1;

            while(hs.contains(less)){

                cnt++;

                hs.remove(less--);

            }

            while(hs.contains(more)){

                cnt++;

                hs.remove(more++);

            }

            res = Math.max(res,cnt);

        }

        return res;

    }