3 rounds of coding interview

1. Simple time-interval problem. (Solved)
2. This was hard problem still looking for a solution: You are given a string of integers without any delimiter "12368910131415101102103...."
   You have to compress this string by the range in the output: "1:3,6,8:10,13:15,101:103..."
   If anyone knows the right solution for this that will be helpful.
3. DFS problem, but the interviewers should work on there communition skill. They were very bad at speaking English fluently and understand it correctly as well. Most of my time was wasted in understanding each other.
4. Design prblem
5. Googliness interview.