Longest Consecutive Sequence

public class Solution {
    public int longestConsecutive(int[] num) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        int len = num.length;
        if(len < 0)
            return 0;
        Map<Integer, Integer > table = new HashMap<Integer,Integer>();
        int[] visit = new int[len];
        for(int i: visit)
            i = 0;
        for(int i = 0; i < num.length;i++)
        {
            table.put(num[i], i);
            
        }
        int result = 1;
        for(int i=0; i<len;i++)
        {
            int count = 1;
            if(visit[i] == 0)
            {
                int tmp = num[i];
                while(table.containsKey(--tmp))
                    {
                        count ++ ;
                        visit[table.get(tmp)] = 1;
                    }
                tmp = num[i];
                while(table.containsKey(++tmp))
                    {
                        count ++;
                        visit[table.get(tmp)] = 1;
                    }
                if(count > result)
                    result = count;
            }
        }
        return result;
        
    }
}