One phone interview, then the onsite interviews. The whole process was smooth and comfortable.

For the four-round onsite interviews, I gave solutions for each question and implemented them with few bugs. Except for the last interview, the interviewer asked me to skip all the details and just implement pseudocode. I didn't understand why I was rejected...

Given the decode function, to implement the encode function:

abckkkkkde -> abc5xkde

For some cases, such as abc3kkkkkde, both encoding 3 and kkkkk result in abc1x35xkde.