String compression - 443

class Solution {
    public int compress(char[] chars) {
        StringBuilder sb = new StringBuilder();
        int  n = chars.length;
        int count = 1;
        sb.append(chars[0]);
        for(int i=1;i<n;i++)
        {
           char curr = chars[i];
           char prev = chars[i-1];
           if(prev==curr)
           {
               count++;
           }
           if(prev!=curr)
           {   if(count>1)
               sb.append(count);
               sb.append(curr);
               count = 1;
           }
        }
        if(count>1)
        {
            sb.append(count);
        }
     
        for(int i=0;i<sb.length();i++)
        {
            chars[i]=sb.charAt(i);
        }
        return sb.length();
    }
}