Question

I need your help with a small problem.

It there a possibility (in Java or an abstract solution) to transform a arbitrary String into an Integer with the property, that the alphabetically ordering does also work with the Integer?

Example:
House < Tree < Zoo in alphabetically order.

I would like to transform those Strings into Integer, so that the ordering is also available. Important is, that the concrete Strings are not known before. That means it should be a unique transformation.

I hope someone can help me.

Regards,
Michael

Answer 1

No, it’s not possible. Let’s say you have two strings which represent 1 and 2. You can always make another string which would fit between them alphabetically e.g.

aa  = 1
ab  = 2
aaa = ???

If you know the strings you’re dealing with have a maximum length, then this is possible. For example, suppose your string has length <= 3. Take a string abc, and convert each letter to a number, where A = 1, B = 2, …, Z = 26. If the string is less than 3 characters long, fill in the blanks at the end with zeroes. Then the value is:

(a * 27 * 27) + (b * 27) + c

Then:

aa  = 756
ab  = 783
aaa = 757