First filter: A test on HackerRank that lasted about 90 minutes. You are given 2-3 programming problems to solve, basically algorithms and data structures. Nothing out of the ordinary, but you have to be fast because time flies.

Second filter: Video interview for soft skills and behavioral questions. Here they ask you the typical Amazon questions about their leadership principles. "Tell me about a time when...", "Describe a situation where...", that kind of thing. It lasts about 45 minutes and you have to have examples prepared.

Third filter: Live coding phone interview. This was the toughest one. They share your screen on an online code editor and you have to solve problems while explaining your thought process.

I had to solve the classic problem of counting islands in a matrix. You are given a grid of 0s and 1s where:

0 = water 1 = land

An island is any group of 1s that are connected horizontally or vertically (not diagonally). You have to count how many islands there are in total.

For example, if you have:

1 1 0 0 1 0 0 1 0 0 1 1

Here there are 3 islands. The first are the connected 1s in the top left. The single 1 on the right is another island. And the two 1s in the bottom right form the third island.