Longest Consequent Sub-sequence - Hashing Problem

To find longest consequent sub-sequence in an array, following is the implementation using hashmap:

	package hashTables.problems;
	import java.util.Arrays;
	import java.util.HashMap;
	import java.util.Map;
	public class LongestConseqSubSeq {
	public static int findLongestConseqSubseq(int a[], int n){
	Map<Integer,Integer> hm = new HashMap<>();
	int max =0,prevMax=0;
	Arrays.sort(a);
	for(int i=0;i<n;i++) {
	if(hm.containsKey(a[i]-1) && !hm.containsKey(a[i])) {
	prevMax++;
	if(prevMax>max) {
	max=prevMax;
	}
	}else if(!hm.containsKey(a[i]-1) && prevMax!=0) {
	prevMax=0;
	}
	hm.put(a[i],i);
	}
	return max+1;
	}
	public static void main(String[] args) {
	int a5[]= {86,77,15,93,35,86,92,49,21,62,27,90,59,63,26,40,26,72,36,11,68,67,29,82,30,62,23,67,35,29,2,22,58,69,67,93,56,11,42,29,73,21,19,84,37,98,24,15,70,13,26,91,80,56,73,62,70,96,81,5,25,84,27,36,5,46,29,13,57,24,95,82,45,14,67,34,64,43,50,87,8,76,78,88};
	System.out.println(findLongestConseqSubseq(a5,a5.length));
	}
	}

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