## SDE1 Interview Questions

- 0of 0 votes
Input: expression_tree | sequence_of_operations

The input is a single line of text with a expression tree and a sequence of operations separated by | character and ended by a \n newline character. Spaces are allowed in the input but should be ignored.

The expression tree is a sequence of 1-character variables A-Z and with sub expression trees formed by parenthesis (expression_tree). Examples: AB, A(B C D), (AB)C((DE)F)

The sequence of operations is a string of with characters R (reverse) or S (simplify)

Reverse means reverse the order of everything in expression tree. Applying reverse twice in a row cancels out. Example: (AB)C((DE)F) | R should print (F(ED))C(BA)

Simplify means remove the parentheses around the very first element in the expression tree and each of its subexpression trees. Applying S multiple times should have same result as applying S once. Example: (AB)C((DE)F) | S should print ABC(DEF)

String process(String input){

}

- -4of 4 votes
..

- 0of 0 votes
Convert Json string to Map

public Map jsonToMap(String t) {

}

- 0of 0 votes
Design Distributed Web Crawler.

- 0of 0 votes
What if server is slow, how to solve

What if one server is down

- 1of 1 vote
Array has N integers，range[0...N-1]。Set S[k], 0 <= K < N as S[K] = {A[K], A[A[K]], A[A[A[K]]],....},

write a function returns the size of the largest set S[K] for this array. return 0 if empty.

ex:

A = [5, 4, 0, 3, 1, 6, 2]

return 4 because S[2] equals {0, 5, 6, 2} 4 elements

- 0of 0 votes
Given an array of integers and a target number, determine if an arithmetic expression using these integers can be evaluated to the target number, you are allowed to use '+', '-', '*', '/'. Follow-up: when evaluating the expression, take operand precedence into account,

public boolean getTarget(int[] nums, int target){

}

exponentia is ok

- 0of 0 votes
find the Closest leaf to a given node in Binary Tree

can you do it in o(n) time

public TreeNode findCloestLeafNode(TreeNode root, TreeNode target){}

no parent pointer

- 0of 0 votes
validate IP in string format and return the uint32 format

‘1.2.3.4’ -> 0x01020304

- 1of 1 vote
Given a n-nery tree and its deep copy, a node in the original tree, return the corresponding node in the copy

public TreeNode getCopyNode(TreeNode root, TreeNode copy, TreeNode node)

- 0of 0 votes
Write the code to find the median of an unsorted array in average linear time.

followup the array is distributed across many machines.

- 0of 0 votes
Write a function to split a SQL query into individual statements.

give you a String which contains a separate Query with a semicolon ";" return all valid queries

Such as

"select name from courseinfo ;; select * from db1 where home = 'usa' ;"

The main thing to consider is that some special cases such as the escape symbol and the quotation marks inside the semicolon

public List<String> getQuery(String queries){

}

- 1of 1 vote
There is a conference room. N people are joining the conference. You have the start time and end time of each of them visiting it. You are asked to determine the maximum number of people that can be inside the room.

Example – Four people are visiting the conference

Person A B C D

Start (hour) 1 3 2 5

End (hour) 4 5 7 10

Answer will be – 3

- 0of 0 votes
Given a group of movies and their start time, assuming that are 1 hour long,

Returns a movie schedule (no time conflict).

enter:

Movie ("Shining", [14, 15, 16])

Movie ("kill bill", [14, 15])

Movie ("Pulp fiction", [14, 15])

One possible result is shining 16, kill bill 15, pulp fiction 14

public void schedule (HashMap <String, List <Integer >> map) {

}

- 0of 0 votes
friend circle. Given a streaming pairs representing friend relationship

(1, 2) means 1 and 2 are friends, (1, 3) means 1 and 3 are friends

Return all its friends.

List<Integer> getFriends (Iterator<List<Integer>> relations, int id){

}

- 0of 0 votes
given a matrix and a target, return if there is a path who’s sum is == target

Input: matrix, integer output: true or false;

- 0of 0 votes
permute the String including case change

"abc".

For example:

abc

ABC

Abc

aBc

abC

ABc

abC

AbC

- 0of 0 votes
implemnt JSON.stringify()

- 0of 0 votes
Given transactions between group of friends. How to minimize the number of transactions by eliminating redundant cash flow paths?

- 0of 0 votes
Design a suggestions list [system design] for words starting with prefix that user has typed on kindle device . The search is based on most frequent item occurring at the top to least frequent item at the bottom. Most frequent item depends on the usage of word globally.

For e.g user types "dra" . There should be a list of suggestions starting with dra such as dragon, drape, dracula etc based on their frequency of usage.

- 0of 0 votes
Design a image slide show 1) put image method 2) get image 3) random method. Random method should return a list of images such that images should be in randomized order and no image should be displayed twice without exhausting all images at once. I used list to store images . I used random class to generate randomly generated images based on the interval {0,list.size()}. But he insist on using randomization without depending on the list size.

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Given a set of points in a plane, determine the position/angle where a yacht of 30 degree angle could be placed such that it could cover maximum points

- 0of 0 votes
Balance a string with parentheses. "a(b)" -> "a(b)"; "(((((" -> ""; "(()())" -> "(()())"; ")ab(()" -> "ab()"; etc...

- 0of 0 votes
can you use union find to Detect Cycle in a Directed Graph? why or why not

- 0of 0 votes
Shell command, there is a log file, you want all the "error" inside the line to find out into another file inside,

What instruction,

- 0of 0 votes
how to design github

- 0of 0 votes
Return the most popular 10 words in the past 24 hours for twitter

Follow up in order to reduce the size of each log, do not write timestamp, how to get the same answer,

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Given a Calendar class (there are three fields, year, month, day) and a number of N,

Implement a function that returns the calendar after N days,

For example, if the input is {2017, 3,20} and 12, then the return is {2017,4, 1}

- 0of 0 votes
implement a Fibonacci iterator

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Now we have one server, one database, what if response time is slow?

How to optimize?