## Algorithm Interview Questions

- 0of 0 votes

AnswersA city represented by a rectangular matrix is divided into plot of lands, and the cost of each plot is known. Find the largest rectangular area of land we can buy, within a budget B.

- sachin323 May 27, 2018 in United States

4 6 7

3 5 2

2 4 5

B = 16| Report Duplicate | Flag | PURGE

Google Software Engineer Algorithm - 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 - 2of 2 votes

AnswerAirbnb: Design webbrowser back button

- aonecoding May 23, 2018 in United States

Your web browser supports will support three actions: back, forward and open. The init webpage is “about:blank”.

Given a sequence of commands. Return the result page.| Report Duplicate | Flag | PURGE

Airbnb Software Engineer Algorithm - 0of 0 votes

AnswersYou have been given a generator string ab from which any number of strings can be generated recursively by inserting ‘ab’ at any location. You have been given an input string to check if that given string is valid or not.(i.e. generated by given with given string.)

- akisonlyforu May 22, 2018 in India

eg.

Input: aabbab

Output: valid

Input: abbaab

Output: Invalid

I could not come up with a algorithm less than O(N*N)| Report Duplicate | Flag | PURGE

Amazon SDE1 Algorithm - 0of 0 votes

AnswerSearch for a sorted integer in an integer array that has been rotated multiple times.

- teli.vaibhav May 14, 2018 in United States| Report Duplicate | Flag | PURGE

Samsung Senior Software Development Engineer Algorithm - 1of 1 vote

AnswersPrint the bottom view of a Binary Tree.

ex-`1 2 3 4 5 7 8 9 10`

result is 4, 8, 5, 9, 7, 10

- teli.vaibhav May 14, 2018 in United States| Report Duplicate | Flag | PURGE

Samsung Senior Software Development Engineer Algorithm - 0of 0 votes

AnswersGiven an alphabet where we do not know the order of the letters also do not know the number of letters.

- teli.vaibhav May 14, 2018 in United States

We are give an input list of tuples where each entry in the list gives an ordering between the 2 letters

Determine the alphabet order.

Ex-

<A, B>

<C, D>

<C, E>

<D, E>

<A, C>

<B, C>

Order is A, B, C, D, E| Report Duplicate | Flag | PURGE

Amazon SDE-2 Algorithm - 2of 2 votes

AnswersAWS phone interview

- aonecoding May 13, 2018 in United States

Find the left view of binary tree

1

/ \

2 3

/\ \

4 5 6

/ /

7 8

/

9

return [1, 2, 4, 7, 9]| Report Duplicate | Flag | PURGE

Amazon Software Engineer Algorithm - 2of 2 votes

AnswersApril Google Interview 1/4

- aonecoding May 06, 2018 in Korea

A = a+b-c-a-b-c-a-b (Tree)

B = b+a+c+a+b-c+b (Tree)

is A equal to B| Report Duplicate | Flag | PURGE

Google Software Engineer Algorithm - 2of 2 votes

AnswersApril Google Interview 3/4

- aonecoding May 06, 2018 in Korea

Maze

N,M array

Level 1 0,0 to N-1,M-1 => Path exsits?

Level 2 if path exists then print path

Level 3 if path exists then print min cost path

Level 4 O(nm log mn) using Priority Queue.| Report Duplicate | Flag | PURGE

Google Software Engineer Algorithm - 0of 0 votes

AnswersWrite a function that receives string with decimal number (i.e. all characters are decimal digits) and prints the sum of all possible substring-numbers, example:

- leonid.ge May 04, 2018 in UK

sum(“123”) = 123 + 12 + 23 + 1 + 2 + 3 = 167| Report Duplicate | Flag | PURGE

Credit Suisse Software Developer Algorithm - 0of 0 votes

AnswerGiven N number of Strings, generate all combination of these String's characters, these Strings must be N long, and must contain only one number of char from each string.

- sapadt May 04, 2018

example: "abc", "def", "ghi" --> adg, adh, adi, aeg ... cfg| Report Duplicate | Flag | PURGE

Morgan Stanley Software Developer Algorithm - 1of 1 vote

AnswersAssume courses labeled by their index in an array. Given a list of pairs where the first element represents a prerequisite course required for the second course, derive an ordered list of courses.

- vmayer99 April 30, 2018 in United States| Report Duplicate | Flag | PURGE

Software Engineer Algorithm - 0of 0 votes

AnswersFor a given set of non-negative integers get the number of subsets that add up to a target value k.

- vmayer99 April 30, 2018 in United States| Report Duplicate | Flag | PURGE

Linkedin Software Engineer Algorithm - 0of 0 votes

AnswersWrite a function to compute n^k. (don't forget negative exponents)

- vmayer99 April 30, 2018 in United States| Report Duplicate | Flag | PURGE

Linkedin Software Engineer Algorithm - 0of 0 votes

AnswersImagine a horizontal corridor bounded by y = y1 and y = y2 lines on a 2D-plane. There are N sensors with centers (x, y) each of which operates in a range (r) on the plane . So, they cover some circular areas on the plane. See the figure below.

`o | _____o___o__|____________ y = y1 o |OOO __________oo|_____O______ y = y2 O | O _ _ _ _ _ _ | _ _ _ _ _ _ | o O | o O O | | O | |`

The question is whether a path exist from x=-inf to x=+inf via corridor without being detected any radar.

Constraints:

1. You are free to move any direction only if you stay in the corridor.

2. You are free to go through corridor borders.

3. N sensors are given as list of (x, y, r) like [(1, 3, 2), (-1, -3, 4)]. x and y are signed integers. r is a unsigned integer.

4. y1 and y2 are integers.

My solution:

1. Create an intersection graph of N sensors by comparing them each other via Euclidean distance`(x1 - x2)^2 + (y1 - y2)^2 <= (r1 + r2)^2`

2. If there is a path between y=y1 and y=y2 through intersected sensors, there do not exist any path from x=-inf to x=+inf. Otherwise, there do exist a path. So, I used BFS to search such a path.

Worst Case Complexity:

1. O(n^2)

2. O(V + E) = O(n + intersection_count)`Total: O(n^2)`

My Best Case Optimization for Intersection Graph:

- engineer06 April 29, 2018 in United States

1. For each sensor, create two events for start and end of circles vertically. y = (y1 - r) and y = (y1 + r)

2. For each sensor, register those two events into an array.

3. Use a line sweep algorithm over 2, which is O(nlogn + intersection_count) and intersection_count may be n^2 at worst case.

I wonder if I should have had a better solution with the worst case < O(n^2).| Report Duplicate | Flag | PURGE

Amazon SDE-2 Algorithm - 0of 0 votes

AnswersYou are given the length and time of occurrence of packet and Queues which process packets. Total processing time for a packet is equal to the length of packet plus the waiting time in queue. For eg lets say we have only one queue for now, and A packet of length 5 comes at t = 1, and another packet of length 4 comes at t = 3. Total processing time for first packet is 5( no waiting time as queue is empty at t = 1) and at t = 3, 2 units of first packet is processed and 3 units remaining so, for second packet 3 units will be waiting time in queue plus 4 units for its length. Total processing time for 2nd packet is 7 units. If there are multiple queues you can add new packet in any of the other queues. Given the time and length of all incoming packets, we need to find the minimum no. of queues required such that total processing time of each packet is less than 10 units. Maximum possible no. of queues are 5. If you require more than 5 queues print -1.

Test Cases Format: First Line contains the number N, the total no. of packets and N following line contains two numbers ti, li where li is length of packet coming at time = ti units.

Test case1:

2

2 7

5 8

Test Case 2:

3

1 3

2 3

3 5

Test Case 3:

3

1 5

2 4

3 8

Output:

Case1: 2

Case2: 1

Case3: 2

Consider the following time table of incoming packets:`time packets-length 1 8 2 5 3 2 4 6`

If you put the packet in queue with minimum time then this will lead to 3 queues:

- ak4017 April 25, 2018 in United States

t = 1:

q1: 8

t = 2:

q1: 7

q2: 5

t = 3:

q1: 6

q2: 4, 2

t = 4:

q1: 5

q2: 3, 2

q3: 6

But its output should be 2 queues:

1) 8 in queue 1

2) 5 in queue 2

3) 2 in queue 1

4) 6 in queue 2| Report Duplicate | Flag | PURGE

Samsung Software Developer Algorithm - 0of 0 votes

AnswersGiven a bar chart which the heights of bars are notated as an array of positive integers. Rectangles can be formed in areas covered by one or more bars. Find the largest rectangle.

- fz April 21, 2018 in United States| Report Duplicate | Flag | PURGE

Software Engineer Algorithm - 6of 6 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 - 0of 0 votes

AnswerGiven list of schedules for different flights in a month, determine maximum number of flights that can be in the air anytime in that month.

- sanjureddy.v April 14, 2018 in United States

Input : list of schedules for flights.- spread over a month.

output: a number - maximum flights that can be in the air

Assumptions: 1. All the given times are in a specific timezone( like GMT).

2. Given Schedules can be any time in the month| Report Duplicate | Flag | PURGE

Google SDE1 Algorithm - 0of 0 votes

AnswerGiven a list of N threads detect a deadlock in the system.

- jddjjd007 April 12, 2018 in United States| Report Duplicate | Flag | PURGE

Google Algorithm - -1of 1 vote

AnswersA sample state of ‘a’:

- prasad.hybris April 03, 2018 in United States

[[2, NULL, 2, NULL],

[2, NULL, 2, NULL],

[NULL, NULL, NULL, NULL],

[NULL, NULL, NULL, NULL]]

FUNCTION foo()

FOR y = 0 to 3

FOR x = 0 to 3

IF a[x+1][y] != NULL

IF a[x+1][y] = a[x][y]:

a[x][y] := a[x][y]*2

a[x+1][y] := NULL

END IF

IF a[x][y] = NULL

a[x][y] := a[x+1][y]

a[x+1][y] := NULL

END IF

END IF

END FOR

END FOR

END FUNCTION| Report Duplicate | Flag | PURGE

Google Cloud Support Associate Algorithm - 0of 0 votes

AnswersYou have a 2 Dimensional Array.

- Rahul Vats March 30, 2018 in United States

1 2 3

4 5 6

7 8 9

Write code to generate all the 7 character strings without any duplicates starting from 4. You can move one block at a time and you can move either horizontally and diagonally. So for example, valid moves from 4 are 4 -> 1 and 4 -> 7. You can visit any node any number of times. so 4141414 is a valid string.| Report Duplicate | Flag | PURGE

Algorithm - 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 - 0of 0 votes

AnswersLanguage : Java

- sarunreddy82 March 28, 2018 in United States

Given a binary tree, print boundary nodes of the binary tree counter-clockwise starting from the root.

For example, boundary traversal of the following tree is “20 8 4 10 14 25 22”

20

8 22

4 12 25

10 14| Report Duplicate | Flag | PURGE

xyz Algorithm - -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 - 0of 0 votes

AnswersQuestion 1: Given an input of an array of string, verify if, turned 180 degrees, it is the "same".

- mche1987 March 27, 2018 in United States

For instance:

[1, 6, 0, 9, 1] => return true

[1, 7, 1] => return false| Report Duplicate | Flag | PURGE

Facebook SDE1 Algorithm - 2of 2 votes

AnswersDropbox

- aonecoding March 21, 2018 in United States

Grid Illumination: Given an NxN grid with an array of lamp coordinates.

Each lamp provides illumination to every square on their x axis,

every square on their y axis, and every square that lies in their diagonal

(think of a Queen in chess).

Given an array of query coordinates,

determine whether that point is illuminated or not. The catch is when checking a query all lamps adjacent to, or on,…| Report Duplicate | Flag | PURGE

Dropbox Software Engineer Algorithm - 2of 2 votes

AnswersMarch 2018 Phone Interview FB

- aonecoding March 17, 2018 in United States

Calculate a moving average that considers the last N values.

Circular Queue (Interviewer didn't agree with the linked list queue that I suggested at first. Said the pointers took space)| Report Duplicate | Flag | PURGE

Facebook Software Engineer Algorithm - 0of 0 votes

AnswerGiven two positive integers represented as linked lists, provide the sum of the numbers as a linked list.

- anonymous March 14, 2018 in United States`1->2->3 4->5->6 ----------- 5->7->9 1->2->3 4->5 ----------- 1->6->8 4->5->6 7->8->9 ----------- 1->2->4->5`

| Report Duplicate | Flag | PURGE

Bloomberg LP Senior Software Development Engineer Algorithm

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