I had a screening call with the recruiter. They offered to conduct a mock interview with two questions, followed by a real interview with the same format. I think the mock interview was slightly easier, but that could have just been because it was easier for me.

You are given an array of zero and nonzero numbers. You need to modify the array in-place by moving all nonzero values to the left of the array. Then, you must return the number of nonzeros that were originally in the array.

The Facebook company store sells stickers that say the word "facebook" on them. We just received a new shipment and have far more stickers than we know what to do with. We came up with a plan: we can make posters by cutting and pasting the letters in the word "facebook" to create other words.

Given a particular source string representing a word on a sticker, write a function that tells me how many stickers of that string I need in order to make a given target string. Your function should take in both a source string and a target string, and return the number of stickers required.