The phone screen lasted one hour, with approximately 50 minutes dedicated to problem-solving and over 5 minutes for asking the interviewer questions.

The interviewer began with some algorithm questions, followed by a coding problem, and concluded with questions about Python.

Coding was done in a Google Doc, and the questions were pasted into it.

(Note: I advanced to the onsite interview, but have not yet received an offer.)

Algorithm questions:

1. What sorting algorithms do you know?
2. When you don't have enough memory to store the array you want to sort, what algorithm do you use and how?

Coding question: Convert a given integer into an Excel-style letter string for columns, such as 0 to A, 1 to B, ..., 26 to AA, etc. This problem seemed simple but had a subtlety: it's not exactly the same as converting between different bases. I struggled a bit, and the interviewer helped me by making up examples. Finally, I figured it out. He was really willing to help. I thought there would be two coding problems, but there was only one.

Questions about Python (which I used for coding):

1. What is the difference between range() and xrange()? What happens to the array generated by range() when the loop ends?
2. He gave me a piece of code to see why it was not efficient and how to modify it. It was concatenating two strings using list.append() for each element of the string.