Given an unsorted array of integers, find the length of the longest consecutive elements sequence.

longestConsecutive.java

/*
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.
*/

public class Solution {
    public int longestConsecutive(int[] num) {
        // Start typing your Java solution below
        // DO NOT write main() function
        if(num.length == 1) return 1;
        
        Arrays.sort(num);
        int cur_max = 1;
        int max = 0;
        int end = num.length - 1;
        for(int i = 0; i < end; i++) {
            if((num[i+1] - num[i]) == 1) {
                cur_max++;
            } else if ((num[i+1] - num[i]) != 0) {
                cur_max = 1;
            }
            if(cur_max > max) {
                max = cur_max;
            }
        }
        
        return max;
    }
}