CareerCup

You are given an old touch smartphone numbers having dial pad and calculator app.


Aim: The goal is to type a number on dialpad.

But as phone is old, some of the numbers and some operations can't be touched.
For eg. 2,3,5,9 keys are not responding , i.e you cannot use them
But you can always make a number using other numbers and operations in Calculator. There could be multiple ways of making a number

.Calculator have 1-9 and +,-,*,/,= as operations. Once you have made the number in Calculator you can copy the number and use it.

You have to find minimum number to touches required to obtain a number.


#Input:#
There will be multiple Test cases .Each test case will consist of 4 lines
1) First line will consist of N,M,O
N: no of keys working in Dialpad (out of 0,1,2,3,4,5,6,7,8,9)
M:types of operations supported (+,-,*,/)
O: Max no of touches allowed

2) second line of input contains the digits that are working e.g 0,2,3,4,6.
3) Third line contains the valued describing operations, 1(+),2(-),3(*),4(/)

4) fourth line contains the number that we want to make .

#Output:#
Output contains 1 line printing the number of touches required to make the number


#Sample Test Case:#
1 // No of test cases
5 3 5 // N ,M, O
1 2 4 6 0 // digits that are working (total number of digits = N),
1 2 3 // describing operations allowed (1--> '+', 2--> '-', 3--> '*' , 4--> '/' )(total number is equals to M)
5 // number we want to make


Answer 3
How 4? 1+4= , "=" is also counted as a touch



2nd Sample Case
3 // No of Test cases
6 4 5 // N ,M, O
1 2 4 6 9 8 // digits that are working (total number of digits = N),
1 2 3 4 // describing operations allowed (1--> +, 2--> -, 3--> , 4-->/)
91 // number we want to make
6 2 4 // 2nd test case
0 1 3 5 7 9
1 2 4 // +, -, / allowed here
28
5 2 10
1 2 6 7 8
2 3 // -, allowed
981

#Output:#
2 // 91 can be made by directly entering 91 as 1,9 digits are working, so only 2 operations
5// 35-7=, other ways are 1+3*7=
9//62*16-11=


Order for computation will be followed as symbols entered, if + comes, it will be computed first


One more example: lets say 1,4,6,7,8,9 works and +,-,* works.
2,3,5 and / doesn't work.
If you have to type 18-> 2 operations. (Each touch is considered an operation),br> If you have to type 5 -> '1+4=' that requires 4 operations. There could be other ways to make '5'.

Complete the puzzle which simulates generic directory structures.
* The solution should be directory agnostic.
* Be succinct yet readable. You should not exceed more than 200 lines.
* Consider adding comments and asserts to help the understading.
* Code can be compiled with javac Directory.java
* Code should be executed as: java -ea Directory (-ea option it's to enabled the assert)
*/


/**
* change the code here.
*/
class Shell {

Shell cd(final String path) {
return this;
}

public String path() {
return "/";
}
}

public class Directory {

public static void main(String[] args) {

final Shell shell = new Shell();
assert shell.path().equals("/");

shell.cd("/");
assert shell.path().equals("/");

shell.cd("usr/..");
assert shell.path().equals("/");

shell.cd("usr").cd("local");
shell.cd("../local").cd("./");
assert shell.path().equals("/usr/local");

shell.cd("..");
assert shell.path().equals("/usr");

shell.cd("//lib///");
assert shell.path().equals("/lib");
}
}

4/5 Round at Uber
Coding: Given a 2D array of either '\' or '/', find out how many pieces this rectangle is divided into graphically.
For a 2X2 matrix with
/\
\/
The matrix split into 5 pieces - the diamond in middle and the four corners. Return 5 as the answer.


5/5 Round at Uber
Design Excel.

2/5 Round at Uber
Bar raiser - Behavioral questions. Coding: Find if a set of meetings overlap. Meeting has a starttime and an endtime with accuracy to minute. All meetings take place in the same day. Do this in O(n) time.

3/5 Round at Uber
Coding: Subset sum. Follow-up: Optimize the solution.

1/5 Round at Uber
Manager : Behavioral questions. Basic system design concepts. Publish/subscribe model. Discussion on Uber architecture.

I've got these trees of integers; they're like regular trees, but they can share nodes.
I need to know if any branch of this tree sums to 100.
7
/ \
8 6
/ \ / \
2 3 9
/ \ / \ / \
5 4 1 100

Follow up question was how would you change the code to handle negative numbers.

Uber
1. Mirror Binary Tree
2. String pattern matching
The matching should cover the entire input string (not partial).
The function prototype should be:
bool isMatch(String str, String pattern)
Some examples:
isMatch("aa","a") → false
isMatch("aa","aa") → true
isMatch("aaa","aa") → false
isMatch("aa","a{1,3}") → true
isMatch("aaa","a{1,3}") → false
isMatch("ab","a{1,3}b{1,3}") → true
isMatch("abc","a{1,3}b{1,3}c") → true
isMatch("abbc","a{1,3}b{1,2}c") → false
isMatch("acbac","a{1,3}b{1,3}c") → false
isMatch("abcc","a{1,3}b{1,3}cc{1,3}") → true
In pattern string, a char followed by {lower, upper} means that the char occur lower to upper(exclusive) times. e.g. a{1, 3} -> a occurs 1 or 2 times.

given a list of numbers, put with + - * / any two number, find the maximum value you can get.
int getMaxNumber(int[] nums){
}

3.1 design: design fb inbox search —> just focus on the post

4.1 binary tree to circular double linked list.
4.2 two arrays, find the common elements of two sorted array. if one array is small, the other is very big.

2.1 career discussion
2.2 divide two numbers with no / or %

1/4 round of FB on-site interview, Master Degree, Hired
1.1 diameter of tree
1.2 find the point which have the maximum overlap of intervals

1 year exp. Interviewed at Cambridge, MA

Round1
LC304. Follow-up: given a char stream instead a string as the input, get the longest substring with at most K distinct characters.

Round2
Find out the area of a number of squares on a plane, an advanced version of LC223.
Had no clue on that problem at all so the interviewer kindly gave another one LC305.

Round3
Similar to LC393 but the interviewer made a slightly different rule for encoding.
Follow-up: decode with utf-16. It took quite a while for me to understand the rules.

Round4
Card game rule: the hand is drawn from a pack of cards (no jokers).
Play cards ONLY when they are
1. 3 of a kind ('AAA' ) or 4 of a kind('AAAA’).
2. a straight flush of 3 or more cards('JQK' or 'A23456...' in the same suit).
Find out whether the player is able to play the whole hand given.
e.g. [Spade A, Spade K, Spade Q, Diamond Q, Heart Q] return false.
[Spade A, Spade K, Spade Q, Diamond Q, Heart Q, Club Q] return true.

given a string of number, you can add a + or * sign between any two numbers, find the maximum value you can get
ex. s = "89" --> 8 * 9 = 72
int maxNumber(String s){}

A new species has been discovered and we are trying to understand their form of communication. So, we start by identifying their alphabet. Tough Mr. Brown managed to steal a vocabulary that has words in it in ascending order and a team already identified the letters. So, we have now ordered words as sequences of numbers, print every letter once in ascending order.

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

alphabet: [3, 4, 2, 1]

Given a string, find the longest substring without repeating any character.

Design a service that keeps track of mobile users as they check in at different locations. This service will get informed of each check-in in real time (a user/location pair) and must be able to answer the following queries in real time:

1. Where is user U right now?
2. What users are at location L right now?

The following requirements apply:

1. A user can only be at one location at a time. If user U checks in at location X and then at location Y, they are no longer at location X.

2. A check-in only valid for at most 2 hours. If user U checks in at location X and then does nothing for 2 hours, they are no longer at location X.

The service should have durable enough storage that you can restart it without losing all of your data It should not store everything in memory.

what kind of DB will you use and how data will be organized and any indexes. If storage is spread out over multiple databases(locations), how is that done?

scalability/availability consideration, how will be distribute multiple servers. what happens when the traffic goes 10x all of sudden. What happens if one of the server goes down.

Google full-time phD candidate w/ work experience.

Q1. On a 1 meter walkroad, randomly generate rain. The raindrop is 1 centimeter wide.
Simulate how raindrops cover the 1 meter [0~1] road. How many drops does it take to fully cover the 1meter?

Q2. Find out the maximum number of isosceles triangles you can make from a plane of points(cannot reuse points)

Q3.Longest holiday - Every city has a different days of holidays every week. You may only travel to another city at the weekends. What is the max days of holiday you can get this year.

Q4.
Design merchandising product data storage service

Give you an unsorted integer iterator
and a percentage that is expressed in double (for example, 0.4 for 40%),
and find the number of the sorted array at the percentage position.
Example: Enter [1 3 2 5 4 6 7 9 8 10], and 0.6, you will return 6
public int findNumber(Iterator<Integer> nums, double percent){
}

An ABC notation in a tree is defined as folllows:
1. "0" means travel left
2. "1" means travel right
3. "Undefined" means hit the root
4. "Not Found" means not present in tree

Given a BST insertion order, {5,2,8,3,6,9,1} find the ABC notation for 6, 1, 10, 2 which is "10","00","NotFound", "0"

Google On-site in May

Create a class with a collection of integers.
Enable 3 APIs:
void append(int x),
int get(int idx),
void add_to_all(int x)，//add x to all numbers in collection
These methods should run in O(1) time.


Follow-up
In addition, implement
void multiply_to_all(int x)
The same required to run in O(1) time

Given a n*m size 2D array with integers from 1 to n*m - 1 in it.
Integers are not sorted. The last position of the matrix stays a movable block.
For each time, you can swap the movable block with any adjacent number.
And eventually you will have the integers sorted and the movable block returned
to its starting position. Think about an approach to print the path.
(You can assume it always have at least a solution)

How to get the repeating decimal pattern of a division? (e.g 1/3, 1/6)

Given input - xyzonexyztwothreeeabrminusseven as a string, return an integer as the sum of all numbers found in the string
Output - 1 + 23 + (-7) = 17

Given a preorder traversal of a BST, print out the inorder transversal of the BST
public void printInorder(int[] nums){}

Implement circular buffer with read & write functions

Coding III
Implement int divide(int a, int b) without division or mod operation.



## Round IV
Behavioral Questions + Project Walk Through + Coding (Validate BST)

## System Design V
Design memcache to enable read, write and delete (single server, non-distributed infrastructure).
Which data structure to go with?
Eviction rules?
How to minimize segmentation?
How to handle concurrency?

## Extra
After two weeks they called me to an extra round of system design.
How to store social graphs?
How to handle concurrent read/write requests(read heavy) on one server.

Given a m x n array filled with 1's & 0's. Find all the rectangles which are filled with all the 1's.


Note : - It is guaranteed that there won't be any overlapping rectangles.

Find Famous person in the list of persons.

A person is a famous person if he doesn't know anyone in the list and everyone else in the list should know this person.

The function isKnow(i,j) => true/ false is given to us. No need to worry about it.

Goal is to find the famous person in O(n) complexity.

Given a array of integers there is one that is repeated several time. How would you compute the length of the sequence of repeated elements.
Assuming the initial array is sorted can you do better than O(n) both for spatial and temporal cost?