Hi I attempted this problem in today's contest and I am very confused about this problem and what I am doing wrong. Firstly, my code is in Java (only language i'm good enough at to attempt these tough problems), and I decided to use HashMaps to store each SINGLE letter as well as each DOUBLE letter (ex: "ab", "ba", "cp", etc.) and got their total values at the end to see which one was in the string the most. That way, I knew how many letters I could keep and just subtracted that from the total string length to find the minimum number of deletions. However, it keeps giving the wrong answer for Test Case 2, and I don't know how to make my code any better. https://codeforces.net/contest/1389/problem/C

import java.util.*;

public class Main {
	public static void main(String[] args)
	{
		 Scanner sc = new Scanner(System.in);
		 int t = sc.nextInt();
		
		 for (int i = 0; i < t; i++)
		 {
			  int max = 0;
			  HashMap<String, Integer> map = new HashMap<String, Integer>();
			  String cyc = sc.next();
			  for (int j = 0; j < cyc.length(); j++)
			  {
				   String single = cyc.substring(j, j+1);
				
				   if (j < cyc.length()-1 && !single.equals(cyc.substring(j+1,j+2)))
				   {
					    String doub = cyc.substring(j, j+2);
					    if (map.containsKey(doub)) 
					    {
					 	     map.replace(doub, map.get(doub)+1);
					 	     max = Math.max(max,  map.get(doub) *2);
					    }
					    else
					    {
						     map.put(doub, 1);
						     max = Math.max(max,  map.get(doub) *2);
					    }
				   }
				   if (map.containsKey(single))
				   {
					    map.replace(single, map.get(single)+1);
					    max = Math.max(max,  map.get(single));
				   }
				   else
				   {
					
					    map.put(single, 1);
					    max = Math.max(max,  map.get(single));
				   }
				
					
			  }
			
			  int fin = cyc.length() - max;
			  System.out.println(fin);
		 }
	}
	
	
}