Write a method to perform basic string compression eg. aabcccccaaa.Should become the ouput a2b1c5a3.

Bad Solution:

public String compressBad(String str)
{
  String mystr= "";
  char last=str.charAt(0);
  int count = 1;
  for(int i=1; i< str.length();i++)
  {
    if(str.charAt(i) == last)
    {
      count++;
    
    }
    else
    {
      mystr +=last + "" + count;
      last =str.charAt(i);
      count =1;
    }
  }
  return mystr + last +count ;
}

This code will not be able to handle all the case.Lets take a look at the runtime of this code.

The runtime is o(p+K to the power of 2)

p=size of the original string.

k=number of character sequences.

So if the string is aabccdeea then there are six character sequence  which will be slow the concatenation operates in o(n to the power of 2).