Associate Software Engineer

Approach (Using DP) :

1) Create a 2-D dp boolean vector(with all false initially) where dp[i][j] states whether s[i...j] is a palindrome or not .

2) Base Case : For every i from 0 to n-1 fill dp[i][i]=1 ( as a single character is always a palindrome )and increment the
counter where counter=0 initially

3) Now, run 2 loops first one from i=n-1 to i=0 (i.e., tarverse from the back of the string) and the second one from
j=i+1 to n .

4) For every s[i]==s[j] , check if(j-i==1 i.e., if s[i] and s[ j] are two consecutive same letters) or if(dp[i+1][j-1]==1 or not
i.e., if the string s[i+1,....j-1] is palindrome or not .

5) Because if the string s[i+1,....j-1] is a palindrome and s[i]==s[j] then s[i] and s[j] can be appended at the starting
and the ending position of s[i+1,...j-1] and s[i...j] will then be a palindrome , so mark dp[i][j]=1 and increment the
counter

6) Finally return the counter


TC : O(N^2) where N=length of the string s
SC : O(N^2)

Approach :
1) I solved it in O(N^2) approach .
2) Sort the array
3) Initially map all the elements of the array to their index in a Hash Map or a Hash Set
4) Now , run 2 for loops and for every x^2 + y^2 ,check if there exists a z^2 s.t x^2+y^2=z^2 and the index of z^2 is
different than both the indices of x and y

Approach :

1) We can store the frequency of every element in the array in a hashmap.

2) We will loop over every index i, and check the frequency of (Target - ARR[i]) is the hashmap:
2.1) If (Target - ARR[i]) is equal to ARR[i], we will check if frequency of ARR[i] . If it is greater than 1 then we will
decrease the frequency of ARR[i] by 2 and add a pair (ARR[i] , ARR[i]) to our answer.

2.2) Else, if the frequency of ARR[i] and Target - ARR[i] is greater than equal to 1 then we add pair (ARR[i], Target -
ARR[i]) to our answer and decrease the frequency of both by 1.

3) If no valid pairs exist, we will return [[-1,-1]].


TC : O(N), where N=size of the array
SC : O(N)

Approach :

spiralPrint(matrix[][], R, C, rows, cols):

1) Check for base cases, i.e. if outside the boundary of the matrix then return.

2) Print the first row from left to right of the matrix i.e from column ‘C’ to ‘cols’, print the elements of the Rth row.

3) Print the last column from top to bottom of the matrix i.e from row ‘R’ to ‘rows’, print the elements of the (cols)th
column.

4) Print the last row from right to left of the matrix i.e from column ‘cols’ to ‘C’, print the elements of the (rows)th row.

5) Print the first column from bottom to top of the matrix i.e from row ‘rows’ to ‘R’, print the elements of the Cth
column.

6) Call the function recursively with the updated values of boundaries, spiralPrint(matrix, R + 1, C + 1, rows - 1, cols -
1).


TC : O(N*M) , where N = number of rows and M = number of columns of the matrix.
SC : O(max(N,M))

Prerequisite to solve this problem : Multithreading

The idea is to create two threads and print even numbers with one thread and odd numbers with another thread.

Below are the steps:

1) Create two threads T1 and T2 , where T1 and T2 are used to print odd and even numbers respectively.

2) Maintain a global counter variable and start both threads.

3) If the counter is even in the Thread T1, then wait for the thread T2 to print that even number. Otherwise, print that
odd number, increment the counter and notify to the Thread T2 .

4)If the counter is odd in the Thread T2, then wait for the thread T1 to print that even number. Otherwise, print that
even number, increment the counter and notify the Thread T1.

Process : A Process is an execution of a specific program. It is an active entity that actions the purpose of the
application. Multiple processes may be related to the same program. For example, if we double-click on Google
Chrome browser, we start a process that runs Google Chrome and when we open another instance of Chrome, we
essentially create a second process.


Program : A Program is an executable file which contains a certain set of instructions written to complete the specific
job or operation on your computer. For example, Google browser chrome.exe is an executable file which stores a set
of instructions written in it which allows us to open the browser and explore web pages.


Major Differences b/w Process and Program :

1) Process is an executing part of a program whereas a program is a group of ordered operations to achieve a
programming goal.

2) The process has a shorter and minimal lifespan whereas program has a longer lifespan.

3) Process contains many resources like a memory address, disk, printer while Program needs memory space on the
disk to store all instructions.

4) When we distinguish between process and program, Process is a dynamic or active entity whereas Program is a
passive or static entity.

5) To differentiate program and process, Process has considerable overhead whereas Program has no significant
overhead cost.

Process : A process is the execution of a program that allows us to perform the appropriate actions specified in a
program. It can be defined as an execution unit where a program runs. The OS helps us to create, schedule, and
terminates the processes which is used by CPU. The other processes created by the main process are called child
process.


Thread : Thread is an execution unit that is part of a process. A process can have multiple threads, all executing at
the same time. It is a unit of execution in concurrent programming. A thread is lightweight and can be managed
independently by a scheduler. It helps us to improve the application performance using parallelism.


Major Differences b/w Process and Thread :

1) Process means a program is in execution, whereas thread means a segment of a process.
2) A Process is not Lightweight, whereas Threads are Lightweight.
3) A Process takes more time to terminate, and the thread takes less time to terminate.
4) Process takes more time for creation, whereas Thread takes less time for creation.
5) Process likely takes more time for context switching whereas as Threads takes less time for context switching.
6) A Process is mostly isolated, whereas Threads share memory.
7) Process does not share data, and Threads share data with each other.

Approach : 

1) Create a new empty string, say RES

2) Iterate through original string STR and check if the current alphabet is a vowel or not.
--If it is not a vowel, append it to the back of RES
--If it is a vowel do nothing

3) The RES string now contains the desired string without vowels.

TC : O(N), where N = length of the string
SC : O(N)

UNION and UNION ALL are used to join the data from 2 or more tables but UNION removes duplicate rows and picks
the rows which are distinct after combining the data from the tables whereas UNION ALL does not remove the
duplicate rows, it just picks all the data from the tables.

A database cursor is a control structure that allows for the traversal of records in a database. Cursors, in addition,
facilitates processing after traversal, such as retrieval, addition, and deletion of database records. They can be
viewed as a pointer to one row in a set of rows.

Working with SQL Cursor :

1) DECLARE a cursor after any variable declaration. The cursor declaration must always be associated with a
SELECT Statement.

2) Open cursor to initialize the result set. The OPEN statement must be called before fetching rows from the result
set.

3) FETCH statement to retrieve and move to the next row in the result set.

4) Call the CLOSE statement to deactivate the cursor.

5) Finally use the DEALLOCATE statement to delete the cursor definition and release the associated resources.

In Java, the final keyword is used as defining something as constant /final and represents the non-access modifier.

1) final variable :
i) When a variable is declared as final in Java, the value can’t be modified once it has been assigned.

ii) If any value has not been assigned to that variable, then it can be assigned only by the constructor of the class.


2) final method :
i) A method declared as final cannot be overridden by its children's classes.

ii) A constructor cannot be marked as final because whenever a class is inherited, the constructors are not inherited.
Hence, marking it final doesn't make sense. Java throws compilation error saying - modifier final not allowed here


3) final class :
i) No classes can be inherited from the class declared as final. But that final class can extend other classes for its
usage.

1) Class(Method) Area: Class Area stores per-class structures such as the runtime constant pool, field, method data, and the code for methods.

2) Heap: It is the runtime data area in which the memory is allocated to the objects

3) Stack: Java Stack stores frames. It holds local variables and partial results, and plays a part in method invocation and return. Each thread has a private JVM stack, created at the same time as the thread. A new frame is created each time a method is invoked. A frame is destroyed when its method invocation completes.

4) Program Counter Register: PC (program counter) register contains the address of the Java virtual machine instruction currently being executed.

5) Native Method Stack: It contains all the native methods used in the application.

SELECT A.ID_Name, B.ID_Name
FROM A
INNER JOIN B ON A.ID=B.ID;

Tip 1 : Prepare the points that you will speak in your introduction prior to the interview.
Tip 2 : Tell about your current cgpa, achievements and authenticated certification
Tip 3 : I told about my role in current internship and what all I do