## SDE-2 Interview Questions

- 2of 2 votes
Given a binary tree print it in inward spiral order i.e first print level 1, then level n, then level 2, then n-1 and so on.

For Ex -

1

2 3

4 5 6 7

8 9 10 11 12 13 14 15

Print- 1 15 14 13 12 11 10 9 8 2 3 7 6 5 4

Follow up question - Extend the algorithm to n-ary tree.

- 3of 3 votes
Given a singly connected linked list, find the largest palindrome in the list in O(1) space.

- 3of 3 votes
Given a linked list consisting of String in each Node . Given just a pointer to the head Node find whether the resultant String formed by combining all the Nodes of the linked list is a palindrome or not in O(1) space and O(n) time.

eg – Consider this linked List structure

“aba” -> “cd” -> “efe” -> “d” -> “caba”

Hence this structure is palindrome .

- 0of 0 votes
Face to Face

Q4) two arrays given to you. First array contains number s. Second array contains key values.

We need to find smallest window in first array which covers all second array elements.

e.g:

Input= {6,7,1,3,2,4,5,2,3,1,2,5}

Keys = {2,5,1}

answer: from 9th index to 11th index is the smallest window.

- 1of 1 vote
Face to face

Q3) stream of numbers coming, get 'n' min elements at any point of time

- 0of 0 votes
Written test:

Q2) in single linked list reverse alternative k nodes.

e.g. k=3 , 1->2->3->4->5->6->7->8->9->10

3->2->1->4->5->6->9->8->7->10

void reverseAlternativeKNodes(node *&head, int k);

- 0of 0 votes
Written Test question:

Q1) Given binary tree find largestPath size from one leaf to another leaf.

int getLargestPathSize(node *root);

- 0of 0 votes
Given an N-ary tree with thousands of nodes in it. Pair (Join) the Leaf nodes which do NOT SHARE the common path. i.e. Two Leaves can be Paired only if they do NOT have Intersecting path.

For example,

A

/ | \

B C D

/ / | \

E F G H

Leaf nodes: E, F, G, H & D

Possible Pairs in O/Ps:

a) (E-F), (G-H) or

b) (E-G), (F-H) or

c) (E-H), (F-G) or

d) (E-D), (F-G) or

e) (E-D), (G-H) or

f) (E-D), (F-H) or

g) (D-H), (F-G) or

h) (D-G), (F-H) or

i) (D-F), (G-H)

Note: If we pair(join) say, (E-F) then we can NOT pair any of the (D-G) or (D-H) as they SHARE the COMMON path from A to C.

i.e. E-B-A-C-F —> (E-F) pair

D-A-C-G —> (D-G) pair

D-A-C-H —> (D-H) pair

- 0of 0 votes
Given a tree, and a pointer to some node in the tree, print the left most element in the same level as that node

- 0of 0 votes
Given an input of the calendar objects of 10,000 employees, input is a time interval T and an employee[] array, find the first interval where all the employees in the employee[] array are free for a minimum time interval T (i.e schedule the meeting)

- 0of 2 votes
Given a binary tree, connect all node in the same level in toggle manner.

Toggle the linking every K level. For first K level, you should link to next right node. Next K you should link to next left and so on.

Node structure is :

struct node

{

int data;

struct node *left, *right, *next;

};

Each level next should point to the next right or left node in the level. For last node in each level, next should be NULL

For ex - if K=2 then for first 2 level of tree connect next pointer from left to right and for next 2 levels connect next pointer from right to left and so on.

- 0of 0 votes
Design a restaurant reservation system - You need to design everything from scratch - Identify actors in the system, identify what all data should be stored in persistence storage (and why). How would you make your design scalable?

- 1of 1 vote
Design a data structure which could perform the following operations in O(1):

- Insert(), Delete(), Search(), getRandom()

getRandom() should pick a "random" element from your data structure, and should not be predictable (for instance always picking the "first" element from your DS)

- 1of 1 vote
You are given a stream of incoming strings. Design a data structure, which at any instant, could tell the 100 most repeated words in constant time.

- 0of 0 votes
Given a very large array of sorted integers, find the number of times a particular integer has been repeated in the array. Required complexity : O(logN)

- 0of 0 votes
Given a string regex and another string pat find whether the pattern is acceptable against given regex string.

Regex string contains following characters and special characters:

1. Normal alphabets – a to z and A to Z

2. ‘$’ – all string should end with all characters preceding $

Example:

Regex :abc$ ,

Pattern: abcd(Not acceptable) , abc(acceptable), ab(Not acceptable), dhfusdhabc(acceptable) etc..

3. ‘^’ – all string should start with all characters exceeding ^

Example: Regex : ^abc

Pattern: abcd(acceptable) , abc(acceptable), ab(Not acceptable), dhfusdhabc(NOT acceptable) etc..

Regex: ^ then only pattern acceptable is null.

4. ‘.’ – any character can be mapped to dot except null

Example 1: Regex : .abc

Pattern: Zabc(acceptable) , abc(NOT acceptable), ab(Not acceptable), habc(acceptable) etc..

Example 2: Regex :a.bc

Pattern: abc(NOT acceptable) , aXbc(acceptable), ab(Not acceptable), habc(NOT acceptable) etc..

5. ‘*’-the character just preceding * can be repeated n time where (n>=0)

Example 1: Regex :abc*de

Pattern: abccccccccccde (acceptable), abcde(acceptable), abcccd(not acceptable)

- 0of 0 votes
Given a list a1,a2,a3….an. Comparison between elements is given like a1>a2, a3>a5, a4>a2…..etc. Find whether there are any situations that we can sort the list in to the ascending order on the basis of comparison. Yes or No , explain the conditions

- 0of 0 votes
Given 2D Array of only 0s and 1s, Find the row which gives max decimal value.

Input: int array[3][3] = {{0,1,0,}{1,1,0},{1,0,1}};

Output : 2(second row)...decimal value is 6

- 0of 0 votes
Find the largest substring in s1, such that all characters in the substring are present somewhere in s2

- -1of 1 vote
Design and implement a scalable multi-player N*N TicTacToe game.

- 3of 3 votes
I had two interviews with Google

first) one with US person...he asked decent question with lot of hints...experience : positive

and

then second) interview with person from India...I prepared for one month but he asked me very tough one graph/tree question...never gave single hint and based on that one question he judged my seven years of experience in Software Development (I never experienced what they say...Google looks for approach and not final answer)

Q.1 : Arrange array in wave form A1 > a2 < a3 > a4 ...

O(n.log-n) (Note: its not A1 >= A2)

Q.2 : Given Graph with Tree characteristics, find one node as root so that height of tree will be minimum

- 3of 3 votes
Imagine a man reading a book.

He can perform only 2 possible actions of reading:

1) read a page in a minute (careful reading),

2) read two pages in a minute (look through).

Nothing else is permitted.

Calculate the number of all possible combinations of book reading ways with given number of pages.

Example: given 3 pages.

Answer is 3 combinations, as follows:

1st: Careful reading (1) - careful reading (1) - careful reading (1),

2nd: Careful reading (1) - look through (2),

3rd: Look through (2) - careful reading (1).

- 2of 2 votes
How do we achieve (google news) personalization.

- -2of 2 votes
Cadbury bar size of 5*3 can be distributed to 4 children.

5*4 can be distributed to 5 children.

6*3 can be distributed to 2 children.

6*4 can be distributed to 3 children. so the whole carton can be distributed among 14 children

Program output shall be 14.

Input/Output Specification: M,N,P,Q are the integer type (M,N values are the ranges for the length of cadburybar P,Q values are the ranges for breadth of Cadbury bar)

Output: Number of children who will receive cadbury bar from the carton.

- 0of 0 votes
2. VeryLongInt

Design a class which can add and subtract integers up to 1000 digits. You can make the following assumptions

No need to handle overflow or underflow (extra credit if you do)

Copy constructor is available

“+” and “-” are binary operators

- 2of 2 votes
1. Balanced Parentheses

Given a string s of parentheses (ex: “(()”), return the minimum number of parentheses that need to be inserted to make it into a well formed string

A well formed (balanced) string of parentheses is defined by the following rules: ● The empty string is well formed. ● If s is a well formed string, (s) is a well formed string. ● If s1 and s2 are well formed strings, their concatenation s1s2 is a well formed string.

Implement

int MinNumInsersertionsForBalancing(const string& s)

- 1of 1 vote
Sort an array of 0s, 1s and 2s

Given an array A[] consisting 0s, 1s and 2s, write a function that sorts A[]. The functions should put all 0s first, then all 1s and all 2s in last.

Example

Input = {0, 1, 1, 0, 1, 2, 1, 2, 0, 0, 0, 1};

Output = {0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 2}

The problem is similar to http://www.csse.monash.edu.au/~lloyd/tildeAlgDS/Sort/Flag/

But they have added 1 trick into the question, You cannot use high = n;

It means don't calculate the length of array.

Can anyone help me in writing the code for this problem ?

- 0of 0 votes
Given a list of sorted arrays, like List<int[]>. Prepare and return a single sorted list.

- 0of 0 votes
Given two Binary Trees (not BST). Each node of both trees has an integer value. Validate whether both trees have the same integers, there could be repetitive integers.

ex-

Tree1:

5

1 6

5 4 3 6

Tree2:

1

3 4

6 5

have identical integers.

- 1of 1 vote
Given a string which may contain parenthesis. We must verify the validity of the string.

ex-

1) "<ad675+-fkmfd>" is a valid string

2) "<[((kskfhdbh7)" is invalid

3) "[<<((shfs8))>>]" is valid

Extension to the question -

Suppose you had a hash table that told you how a parenthesis starts and how it ends as a key value pair, how would you then validate the string.

ex - <key,value> = < '(' , ')' > indicates '(' is a start parenthesis and ')' should be the end of that paranthesis.

<'A','&'> indicates that 'A' is a start parenthesis and '&' is the end parenthesis.

Note: Validity means a parenthesis that starts, must end.