Software Engineer (Android) Facebook Interview

Status: Working as Software Engineer
Position: Software Engineer(Android) in Facebook
Location: Menlo Park

Technical Phone Screen
Write an algorithm to print all combinations of characters that could represent using the numbers typed: Letter Combinations of a Phone Number

Onsite Interview (5 rounds)
Round 1: (Whiteboard coding)
Trapping Rain Water -

Round 2: (Architecture & Design of Android application)
Design a android application to change phone wallpaper whenever user unlocks the phone screen. The wallpaper should be random publicly shared pictures from your facebook friend’s album.

Round 3: (Whiteboard coding)
One Edit Distance -

Round 4: (Behaviour and Coding)
Bunch of questions from resume till my interest, likes, dislikes, passion, strengths & weakness.
Coding question
Maximum Swap -

Round 5: (Architecture and Design of Android Application)
Design an Android application similar to Instagram to display the users uploaded photos as feed