A recruiter reached out to me and set me up for an interview. They emailed me prep material for the phone interview. I scheduled the phone interview for a date a month later.

There were two engineers on the phone call. Their introductions were short, and I kept mine short to get more time for the coding problem. They used CollabEdit for reviewing and sharing code.

There was only one coding question, followed by wrap-up time for me to ask them questions.

The entire interview lasted one hour. They asked me to explain my solution and its space and time complexities. They also asked how I could improve it. (99% of the time, the answer to improve time complexity is to compromise on space complexity, meaning introduce a hashmap into your solution).

Overall, it was a decent experience.

Given two words as strings, determine if they are isomorphic. Two words are called isomorphic if the letters in one word can be remapped to get the second word. Remapping a letter means replacing all occurrences of it with another letter while the ordering of the letters remains unchanged. No two letters may map to the same letter, but a letter may map to itself.

• Example:

  • given "foo", "app"; returns true we can map 'f' -> 'a' and 'o' -> 'p'

  • given "foo", "boa"; returns false we can map 'f' -> 'b', 'o' -> 'o'; we can't map 'o' -> 'a'

  • given "bar", "foo"; returns false we can't map both 'a' and 'r' to 'o'

  • given "turtle", "tletur"; returns true we can map 't' -> 't', 'u' -> 'l', 'r' -> 'e', 'l' -> 'u', 'e' -> 'r'

  • given "ab", "ca"; returns true we can map 'a' -> 'c', 'b' -> 'a'