CareerCup

Implement a fair mutex

An array is called a Good Array if the elements continually increasing or continually decreasing or continually decrease and then increase.
Question 1: He asked how will you tell whether a given array is a good array or not.
Question 2: Given an array, you are allowed to add any number of values to each of the element. Find the minimum sum of elements that can make the array a good array.

A software-based LRU Cache replacement algorithm has to be implemented for a Single Touch/Multi-Touch Cache. Single Touch can occupy at least 30% of the total cache space. A key accessed for the first time will appear in the Single Touch cache. When accessed multiple times, this will be part of the multi-touch cache. Also, multiple threads will access the cache. Following are the functions allowed for cache access.
1. get(key): returns the value against the key if present else return NULL
2. set(key, value): set the value against the key

Given a tree, and there will be treasure in one of the nodes. We can query any node, it will return the node itself if it contains the treasure or it returns the branch which leads to the treasure. we need to find out the treasure in minimum number of queries.

Design a jenkins kind of system

Imagine someone maliciously duplicated every file on your computer, and completely randomized their names and locations on your hard drive. Discuss an efficient way to clean up your drive of all these duplicates.

Two very very large files F1, F2 containing key, value pairs. Write these key, values to a third file without any duplicates.

Design real time tail log search

Build a key-value data structure that allows the user to take a snapshot of the data. The user can read the key-value store from any snapshot.

Structure has the normal key/value like methods plus something like
snapshot = dataStructure.takeSnapshot()
value = dataStructure.get(key, snapshot)
void dataStructure.deleteSnapshot()

A table has some number of balls at various positions on a line segment. All are moving with same speed in one or the other direction. Wherever a collision occurs they change direction. A ball falls from the edges of the table. Find the time when all balls fall of the table given initial position of each ball and speeds

Find the maximum number of concurrent sessions in the following data with the first value representing start time and last value end time. The input is not necessarily sorted.
Input: (2,5), (3,6), (8,10),(10,12),(9,20)
Output: 3 (from 8 to 20)
Input: (2,5), (3,6), (8,10),(9,12),(12,20)
Output: 2 (from 8 to 12 or 2 to 6)

Given a list L of video names and their watch rates, write a function that will return the videos with the top 10 watch rates. Video names may appear more than once.

Example:

L = [(‘abc’, 10), (‘def’, 15), (‘ghi’, 10), (‘abc’, 12), …, (‘xyz’, 100)]

The function should return [‘xyz’, ‘abc’, …, ‘def’, ‘ghi’]

Write a function that takes a list L and returns a random sublist of size N of that list. Assume that the indexes must be in increasing order. That is, you cannot go backwards.

Example:

L = [1, 2, 3, 4, 5]
N = 3

The function should return one of these lists:

[1, 2, 3]
[1, 2, 4]
[1, 2, 5]
[1, 3, 4]
[1, 3, 5]
[1, 4, 5]
[2, 3, 4]
[2, 3, 5]
[2, 4, 5]
[3, 4, 5]

Consider an undirected tree with N nodes, numbered from 1 to N. Each node has a label associated with it, which is an integer value. Different nodes can have the same label. Write a function that, given a zero indexed array A of length N, where A[j] is the label value of the (j + 1)-th node in the tree and a zero-indexed array E of length K = (N – 1) * 2 in which the edges of the tree are described, returns the length of the longest path such that all the nodes on that path have the same label. The length is the number of edges in that path.

Example:

A = [1, 1, 1, 2, 2]
E = [1, 2, 1, 3, 2, 4, 2, 5]

This tree is shown below. A node follows the form label, value.

----------1, 1

-----1, 2 1, 3

2, 4 2, 5
The function should return 2, because the longest path is 2->1->3, and there are 2 edges in this path.

Assume that 1 <= N <= 1000 and each element of the array A is an integer in the range [1, 1000000000].

Given a string A consisting of n characters and a string B consisting of m characters, write a function that will return the number of times A must be stated such that B is a substring of the repeated A. If B can never be a substring, return -1.

Example:
A = ‘abcd’
B = ‘cdabcdab’
The function should return 3 because after stating A 3 times, getting ‘abcdabcdabcd’, B is now a substring of A.

You can assume that n and m are integers in the range [1, 1000].

Given 1-D list of co-ordinates determine if interval (a,b) is covered

Ex - [(2,5), (5,7),(1,4)] and interval = (1,6)
return true
Explanation - Points 1 to 6 lies in list of interval given 1 to 4. 2 to 5 and 5 to 7.

[(1,4),(6,7),(2,5)] and interval - (1,6)
return false
Explanation - Distance between 5 to 6 is not covered in the list given so return false

Compare two documents(string array) based on n grams.
e.g doc1 – Today is Sunday.
doc2 – Today is Saturday
if n = 2 then number of duplicates is 1 (Today is)
if n = 1 then number of duplicates is (Today, is)
if n = 3 duplicates is 0

Given a bench with n seats and few people sitting, tell the seat number each time when a new person goes to sit on the bench such that his distance from others is maximum

Given a room with thief on left side of the room with finite number of sensors. He has to reach on right side missing the sensors. Each sensor is placed at any random point in the room and has its coverage in the radius r. Find out if the thief can reach to the right side without touching the range of any sensor.

Given an infinite chessboard, find minimum no. of steps for a knight to reach from the origin to (x, y).
Extension A list of forbidden coordinates are introduced where knight can’t reach. Handle this in your code. Make sure the infinite loop is handled since the board is infinite.

Given a matrix of people(denoted by small alphabets) and bikes(denoted by capital alphabets), find the nearest bike for a given person.
How will you change your solution if you have to find bikes for a set of people? (assuming multiple bikes can be at the same distance from 1 person)

Given an array of n integers, find the lexicographically smallest subsequence of length k.

Given a list of player names and their scores – {Carl, 70; Alex, 55; Isla, 40}, design a data structure that can support following modules in optimal time-
i) updateEntry(string name)
ii) getEntryFromRank(int rank)

Given an input stream of boolean values, design a data structure that can support following modules in optimal time-
i) setTrue(index)
ii) setFalse(index)
iii) setAllTrue()
iv) setAllFalse()
v) getIndex(index)

Given two strings, A and B, of equal length, find whether it is possible to cut both strings at a common point such that the first part of A and the second part of B form a palindrome.

Extension1. How would you change your solution if the strings could be cut at any point (not just a common point)?
Extension2. Multiple cuts in the strings (substrings to form a palindrome)? Form a palindrome using a substring from both strings. What is its time complexity?

Given a stream of integers, a value k and a value w, consider the integers in the window w and chop off greater k and smaller k elements from the window w. From the remaining elements, compute the average.

Implement the version control map system which takes the snapshot of the versions of data. Implement the following functions:

put(key, value) -> puts the value again the key in the latest version of the map

get(key) -> get the value of the key for the latest version of the data

snapshot() -> take a snapshot and increment the version

getValVersion(version id, key) -> return value of the key of the particular version

Given various subsequences of an array, print the overall array:

Example: [1, 3, 5], [1, 3, 9], [9, 5]

Array : [1, 3, 9, 5]

A graph has N vertices numbered from 1 to N. We have two lists. One list M consisted of edges between vertices. The other list K consists of restricted paths. We have to add edges one by one from M and check whether the addition of the particular edge leads to a path between the restricted edges given in K. If it creates a path, we have to discard the edge.

Example: N = 4; K = {(1, 4)}; M = {(1, 2), (2, 3), (3, 4)}. Here, addition of edge (3, 4) will create a path between 1 and 4. Hence we discard edge (3, 4)

You are given 2 strings which are exactly same but 1 string has an extra character. Find that character.