## Facebook Interview Questions

- 0of 0 votes

AnswersYou have two sorted arrays, where each element is an interval. Now, merge the two array, overlapping intervals can be merged as a single one.

- Seetha November 11, 2018 in United States

I/P :

List 1 [1,2] , [3,9]

List 2 [4,5], [8, 10], [11,12]

O/P [1,2], [3,10], [11,12]| Report Duplicate | Flag | PURGE

Facebook Software Developer - 0of 0 votes

AnswerI/P [8, 3, 2, [5, 6, [9]], 6]

- Seetha November 11, 2018 in United States

O/P 8+3+2+2*(5+6+3*(9))+6 => 95| Report Duplicate | Flag | PURGE

Facebook Software Developer Arrays - 0of 0 votes

Answersfind all numbers the sum of cube of each digits is the number itself

- Aamir November 09, 2018 in United States

ex:153=1^3+5^3+3^3| Report Duplicate | Flag | PURGE

Facebook Software Engineer Intern - 0of 0 votes

AnswersYou are given an array A of size N and Q queries. For each query, you are given two indices of the array L and R. The subarray generated from L to R is reversed. Your task is to determine the maximum sum of the subarrays.

- Sameer October 29, 2018 in United States

Note: After each query is solved, the array comes to its initial states.

Input format

First line: Two space-separated integers N and Q

Next line: N space-separated integers denoting the array elements.

Next

Q lines: Two space-separated integers in every line denoting the values of Li and Ri

Output format

For each query, print the required answer in a new line.

5 2

3 -1 4 2 -1

3 4

1 2

//output

8

9| Report Duplicate | Flag | PURGE

Facebook Software Developer - 0of 0 votes

AnswersConvert infix to postfix and evaluate postfix expression.

- user October 28, 2018 in United States

For example: 4 // number of variables

g = 2

p = 3

t = 1

w = 2

3 // number of equations

g + p x t - w x p

t - g + t - w

e + t x t - m

Output: -1 //for first equation

-2 //for second equation

Compilation Error // for third equation| Report Duplicate | Flag | PURGE

Facebook Testing / Quality Assurance - 0of 0 votes

AnswersConvert infix to postfix and evaluate postfix expression.

- user October 28, 2018 in United States

For example: Input:

3 // number of variables

a = 1

b = 2

c = 2

2 // number of equations

a x b + a x c + b x c

a x c - b / c + c x c

Output: 8 //for first equation

5 // for second equation| Report Duplicate | Flag | PURGE

Facebook Testing / Quality Assurance - 1of 1 vote

AnswerHow to evaluate a mathematical expression by compiler design. The program will ask the user to input a value (say n). Then user will input n lines of input each of which contains an identifier and its corresponding value. Then program will ask the user again to input a value (say m). Then user will input m lines of expressions. Calculate the final value for each of the given expression using first n lines of input. If you can't evaluate any expression from given numbers of identifiers then output 'Compilation Error'. Allowed mathematical operators are +(add), -(subtract), x(multiply), /(divide).

- user October 27, 2018 in United States

Example: a = 1

b = 2

c = 2

a x b + a x c + b x c output 8

a x c - b / c + c x c out put 5

g = 2

p = 3

t = 1

w = 2

g + p x t - w x p output -1

t - g + t - w output -2

e + t x t - m output compilation error| Report Duplicate | Flag | PURGE

Facebook Software Engineer - 2of 2 votes

AnswersGiven the root of a binary tree, print the nodes column wise and row wise.

`..............6 ............/....\ ...........9......4 ........../..\......\ .........5....1.....3 ..........\........./ ...........0.......7`

The answer would be 5 9 0 6 1 4 7 3.

- Champaklal October 26, 2018 in United States| Report Duplicate | Flag | PURGE

Facebook Software Developer Algorithm - 2of 4 votes

AnswersGiven a tree with n nodes and each node has 0 - n coins. The total coin number is n. Now we need to move the coins such that each node has exactly one coin. What's the minimum moves required? Each move can only move one coin to an adjacent node. (Notice it's not necessary to be a binary tree)

- aonecoding4 October 22, 2018 in United States`For example tree: 1 | \ \ 0 1 0 | 3 will needs at least 4 moves.`

| Report Duplicate | Flag | PURGE

Facebook Software Engineer - 1of 1 vote

AnswersGiven a list of Contacts, where each contact consists of a contact ID and a list of email IDs. Output a unique list of contacts by removing duplicates. Two contacts are considered to be the same, if they share at least one email ID.

- MM2181 August 19, 2018 in United States| Report Duplicate | Flag | PURGE

Facebook Web Developer - 2of 2 votes

AnswersGiven an integer, print an English phrase that describes the integer (eg, "Two hundred and thirty four", “One Thousand, Two Hundred and Thirty Four”)

- MM2181 August 19, 2018 in United States| Report Duplicate | Flag | PURGE

Facebook Web Developer - 1of 1 vote

AnswersYou are given n points (x1, y1), (x2, y2), ..... (xm, ym) of a two dimensional graph. Find 'n' closest points to (0,0) [ n <= m ]. Euclidean distance can be used to find the distance between 2 points.

- MM2181 August 19, 2018 in United States| Report Duplicate | Flag | PURGE

Facebook Web Developer - 0of 0 votes

Answerswrite a class that 1) calculates the average of the stream, 2) provides an API read the average.

- samayragoyal990 August 10, 2018 in United States

Handle overflows as the numbers can be very large and not fit into double/long.| Report Duplicate | Flag | PURGE

Facebook SDE-3 Coding - -1of 3 votes

AnswersGiven an array of lower case strings, the task is to find the number of strings that are special equivalent.

- boony August 09, 2018 in United States

Two strings are special equivalent if they can be made equivalent by performing some operations on one or both string

swapEven : swap a character at an even-numbered index with a character at another even-numbered index

swapOdd : swap a character at an odd-numbered index with a character at another odd-numbered index

Input : arr = {"abcd", "cbad", "bacd"}

Output : 2

The 2nd string can be converted to the 1st by swapping

the first and third characters. So there are 2 distinct

strings as the third string cannot be converted to the

first.

string input[] = {"abcd", "acbd", "adcb", "cdba",

"bcda", "badc"};

ans =4| Report Duplicate | Flag | PURGE

Facebook Software Engineer - 2of 2 votes

AnswersGiven 2 strings representing very large numbers (these are not representable as a BigInteger or other various type) write a method for adding the two numbers and returning their sum.

- Scott.T.Rogers July 06, 2018 in United States| Report Duplicate | Flag | PURGE

Facebook Senior Software Development Engineer Algorithm - -3of 5 votes

Answerword look up

- bryan July 06, 2018 in United States| Report Duplicate | Flag | PURGE

Facebook Data Structures - 2of 2 votes

AnswersI was asked to design a system on a whiteboard which simulate a executor.

- Patrick July 01, 2018 in United States

This system has a method that is being triggered every second. I need to add logic to the method (i.e. run jobs).

There is also a method called job_arrived() that is called when a new job arrives.. I need to implement it as well.

I needed to implement a system which tries to run each job right when it is arrived (it has a return value that gets a success status from a black box service). if the job ran successfully that's the end of it..

if not I need to re-run it after 2 seconds (and if that fails as well - there will be no re-runs).

of course - more than one job can be accepted each second.

I was asked to describes the system (describe the classes and method) and consider the system to be large scale one (meaning.. threading is in order here..).

The answer I gave was apparently not multi threaded enough..

any idea to what I should have done?

Thanks guys| Report Duplicate | Flag | PURGE

Facebook Software Developer Java - 5of 5 votes

AnswersCongrats on aonecode member A.P. for signing the offer with FB! Thanks for sharing the experience with us.

- aonecoding May 24, 2018 in United States

phone:

postorder tree traversal recursive -> iterative

add two binary number

on-site:

1 ring buffer

2 merge intervals

3 Leetcode alien dictionary

4.sort list of words| Report Duplicate | Flag | PURGE

Facebook Software Engineer Algorithm - 1of 1 vote

AnswersGiven a number, rearrange the digits of that number to make a higher number, among all such permutations that are greater,one of them is the smallest, Find the smallest greater permutation (the next Permutation).

- sarunreddy82 May 13, 2018 in United States

Examples:

next_permutation (12) = 21

next_permutation (315) = 351

next_permutation (583) = 835

next_permutation (12389) = 12398

next_permutation (34722641) = 34724126| Report Duplicate | Flag | PURGE

Facebook Java - -4of 4 votes

AnswersIf b == “1”:

- TubbyOPPO May 09, 2018 in England

quit()| Report Duplicate | Flag | PURGE

Facebook Software Engineer - 1of 1 vote

AnswersGiven a binary tree, where each node represents an integer, find the max value of path sum.

- LeetCoder May 07, 2018 in United States| Report Duplicate | Flag | PURGE

Facebook Android Engineer Trees and Graphs - 5of 5 votes

AnswersFB On-site March

- aonecoding April 21, 2018 in United States

Q: Find number of Islands.

XXXOO

OOOXX

XXOOX

Return 3 islands.

1 1 1OO

OOO2 2

3 3OO 2

Followup: If the board is too big to fit in memory, how to get the number?| Report Duplicate | Flag | PURGE

Facebook Software Engineer Algorithm - 1of 1 vote

AnswersInterleave list of lists in Java

- npkatre102 April 18, 2018 in United States

Example:

input = [[1,2,3], [9, 0], [5], [-4,-5,-2,-3,-1]];

output = [1,9,5,-4,2,0,-5,3,-2,-3,-1]| Report Duplicate | Flag | PURGE

Facebook Software Developer - 0of 0 votes

AnswersGiven an array of n elements return true if 3 of the sum of 3 elements is equal to a constant c

- mapardotl April 10, 2018 in United States for Facebook groups

Example array a[6,2,3,4] constant c = 9

if a[1] + [2] + [3] == c return true

The size of the array is n

If any set of 3 elements is equal to the constant c, then return false| Report Duplicate | Flag | PURGE

Facebook Software Engineer / Developer Java - 2of 2 votes

AnswersGiven a string with alpha-numeric characters and parentheses, return a string with balanced parentheses by removing the fewest characters possible. You cannot add anything to the string.

- genaker April 05, 2018 in United States| Report Duplicate | Flag | PURGE

Facebook Software Developer - 2of 2 votes

AnswersGiven a collection of two dimensional points and a number k, return the k closest points to (0,0) by Euclidean distance.

- genaker April 05, 2018 in United States| Report Duplicate | Flag | PURGE

Facebook Software Developer - 1of 1 vote

AnswersGiven a string as input, return the list of all the patterns possible:

`'1' : ['A', 'B', 'C'], '2' : ['D', 'E'], '12' : ['X'] '3' : ['P', 'Q']`

Example if input is '123', then output should be [ADP, ADQ, AEP, AEQ, BDP, BDQ, BEP, BEQ, CDP, CDQ, CEP, CEQ, XP, XQ]

- ngupta32@hawk.iit.edu March 30, 2018 in United States| Report Duplicate | Flag | PURGE

Facebook Software Engineer Algorithm Coding Data Structures - 1of 1 vote

AnswersMove[inplace] the non zero elements at the one end(end of array) and return the numbers of non zero elements in output array

- rituraj.raj March 28, 2018 in India for London office

Solution : https://www.geeksforgeeks.org/move-zeroes-end-array/| Report Duplicate | Flag | PURGE

Facebook Android Engineer - 0of 2 votes

Answerwhat is UI/Main Thread in android.

- rituraj.raj March 28, 2018 in India for London office

when you can use Thread over Service| Report Duplicate | Flag | PURGE

Facebook Android Engineer - -1of 1 vote

AnswersQuestion 2: Given a number 'k', return the corresponding row, given the pattern:

- mche1987 March 27, 2018 in United States

k => output

0 => []

1 => ["0", "1", "8"]

2 => ["00", "11", "69", "96", "88"]

3 => ["000", "111", "101", "888", ...] // and so on ...| Report Duplicate | Flag | PURGE

Facebook SDE1 Algorithm

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