First non-repeating character in a stream

class Solution
{
    public String FirstNonRepeating(String A)
    {
        // code here
        
        
        int[] count = new int[26];
        
        Queue<Character> que = new LinkedList<>();
        
        StringBuilder sb = new StringBuilder();
        
        for(int i=0; i< A.length(); i++)
        {
            
            char ch = A.charAt(i);
            int value = ch - 'a';
            
            count[value]++;
            
            
            if(count[value] <= 1)
            {
                
                que.add(ch);
                
            }
            else
            {
                
                que.remove(ch);
                
            }
            
            
            if(que.isEmpty())
            {
                
                sb.append('#');
                
            }
            else
            {
                
                sb.append(que.peek());
                
            }
            
            
            
            
        }
        
        return sb.toString();
        
        
        
        
        
        
        
        
        
        
        
        
        
    }
}