It is so interesting to meet the peer second time in less than a week. I had good time to learn Go language through the peer's performance. One major advice I had after the peer ran the web compiler test cases is to add back tracking on line 35, so the code could pass all test cases. I explained to the peer that parent node will ask child node to back track the element to its original dot value since parent node will try its next option.
This mock interview is so much fun, since last time I was complained not to give out any hint, leave first 30 minutes for the peer to reach his full potential. The peer gave the time complexity analysis and mentioned that he learned the recursive tree through cracking code interview book.
Here is Go code I reviewed, which also passes all test cases.