Facebook Software Engineer Interview Questions & Reviews

what can FB do to beat its competitors in my country, where it is not the most popular social network.

search needle in haystack problem

Implement a function
char* readLine();
which returns single lines from a buffer. To read the buffer, you can makes use of a function
int read(char* buf, int len)
which fills buf with upto len chars and returns the actual number of chars filled in. Function readLine can be called as many times as desired. If there is no valid data or newline terminated string available, it must block. In order to block, it can use read function which in turn will block when it doesn't have anything to fill the buf.

Implement a function rotateArray(vector<int> arr, int r) which rotates the array by r places. Eg 1 2 3 4 5 on being rotated by 2 gives 4 5 1 2 3.

Implement a function string balanceParanthesis(string s); which given a string s consisting of some parenthesis returns a string s1 in which parenthesis are balanced and differences between s and s1 are minimum.
Eg - "(ab(xy)u)2)" -> "(ab(xy)u)2"
")))(((" -> ""

How will you design TinyUrl?

How will you design facebook newsfeed. Focus was on a design which could handle the huge number of status updates and display them on each of the user's friend's wall.

Find Kth smallest element in a BST.

Implement needle-in-a-haystack (string search). Make it more robust.

Implement a queue data structure given only stacks. What is the time complexity of enqueuing and dequeuing operations?

Given a Binary Search Tree, iterate over the elements without using recursion.

Given a set of non-overlapping integer ranges (1,3) (5,8), etc., and an input integer, what is the best way to organize the data and allow for quick search based on the input, etc.

Given a telephone number, find all the permutations of the letters assuming 1=abc, 2=def, etc.

Print a singly-linked list backwards, in constant space and linear time.

Convert a binary search tree to a sorted, circular, doubly-linked list, in place (using the tree nodes as the new list nodes).

Given a set of words, group them into sets of anagrams.

Given a string, remove all the duplicate characters (not necessarily consecutive)