The first phase is to pass their online take-home quiz, which deals with basic algorithms, data structures, and some logical questions. Nothing much to stress about.

After you pass that, they invite you to the phone interview, through a third-party interviewer on Google Hangouts. Make sure you're well-versed to explain your old projects and have a normal conversation.

Given a 2D grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water.

Example 1:

Input: 11110 11010 11000 00000

Output: 1