Longest subsequence-1

//Longest subsequence-1

import java.io.*;
import java.util.*;

class IntArray {
    public static int[] input(BufferedReader br, int n) throws IOException {
        String[] s = br.readLine().trim().split(" ");
        int[] a = new int[n];

        for(int i = 0; i < n; i++)
          a[i] = Integer.parseInt(s[i]);

        return a;
    }

    public static void print(int[] a) {
        for(int e : a)
          System.out.print(e + " ");
        System.out.println();
    }

    public static void print(ArrayList<Integer> a) {
        for(int e : a)
          System.out.print(e + " ");
        System.out.println();
    }
}

class GFG {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int t = Integer.parseInt(br.readLine());

        while(t-- > 0) {
            int n = Integer.parseInt(br.readLine());
            int[] a = IntArray.input(br, n);
            Solution obj = new Solution();
            int res = obj.longestSubseq(n, a);
            System.out.println(res);
        }
    }
}

class Solution {
    public static int longestSubseq(int n, int[] a) {
        Map<Integer,Integer> mm = new HashMap<>();
        int ans = 0;
        
        for(int i = 0; i < n; i++) {
            mm.put(a[i], 1 + Math.max(mm.getOrDefault(a[i] - 1, 0), mm.getOrDefault(a[i] + 1, 0)));
            ans = Math.max(ans, mm.get(a[i]));
        }
        
        return ans;
    }
}