Question
You are given a string like “aaaabbbcc”, do an in place conversion which write frequency of each charater(which come continuosly) with that character.
Example:
input: aaabbbcc
output: a3b2c2
Solution
The most important point is whether or not you find the special cases, and did you clarify how to handle them.
First special case is only 1 character, should you append a ‘1’ or not. Note that this question requires ‘in place’ conversion. So ‘1’ is not supposed to be appended after single-occurance character. This is really important to know, if the question does not specify. (though sometimes, the question asks you to apppend a ‘1’, eg. here).
Second case is when occurance >= 10. We could not simply append (‘0’ + numberOfOccurance), because the number could be 12. This is another very important case to take note.
The code can be seen anywhere.