Java Developer

You are given an integer ‘N’, your task is to find and return the N’th Fibonacci number using matrix exponentiation.

Since the answer can be very large, return the answer modulo 10^9 +7.

Fibonacci number is calculated using the following formula:

F(n) = F(n-1) + F(n-2), 
Where, F(1) = F(2) = 1.

For Example:

For ‘N’ = 5, the output will be 5.

You are given an integer ‘N’ , calculate and print the sum of :

LCM(1,N) + LCM(2,N) + .. + LCM(N,N) 

where LCM(i,n) denotes the Least Common Multiple of the integers ‘i’ and ‘N’.

You are given a string 'S'. Your task is to check whether the string is palindrome or not. For checking palindrome, consider alphabets and numbers only and ignore the symbols and whitespaces.

Note :

String 'S' is NOT case sensitive.

Example :

Let S = “c1 O$d@eeD o1c”.
If we ignore the special characters, whitespaces and convert all uppercase letters to lowercase, we get S = “c1odeedo1c”, which is a palindrome. Hence, the given string is also a palindrome.

You are given an array of integers. You need to sort the array in ascending order using quick sort.

Quick sort is a divide and conquer algorithm in which we choose a pivot point and partition the array into two parts i.e, left and right. The left part contains the numbers smaller than the pivot element and the right part contains the numbers larger than the pivot element. Then we recursively sort the left and right parts of the array.

Example:

Let the array = [ 4, 2, 1, 5, 3 ]
Let pivot to be the rightmost number.

After the 1st level partitioning the array will be { 2, 1, 3, 4, 5 } as 3 was the pivot. After 2nd level partitioning the array will be { 1, 2, 3, 4, 5 } as 1 was the pivot for the left part and 5 was the pivot for the right part. Now our array is sorted and there is no need to divide it again.

You are given a positive integer 'N'. Your task is to return all the prime numbers less than or equal to the 'N'.

Note:

1) A prime number is a number that has only two factors: 1 and the number itself.

2) 1 is not a prime number.

Explain Different keys in DBMS

Two Table were given. we need to write a query for inner join.

You have been given a string ‘S’.

You must return the string ‘S’ sorted in decreasing order based on the frequency of characters.

If there are multiple answers, return any of them.

Example :

Let 'S'= “abAb”. 

Here the characters ‘a’ and ‘A’ have frequency 1 and character ‘b’ has frequency ‘2’.  

Therefore the sorted string is “bbAa”. 

Print the following pattern

Pattern for N = 4

The dots represent spaces.

You are given an array consisting of 'N' positive integers where each integer is either 0 or 1 or 2. Your task is to sort the given array in non-decreasing order.

Note :

1. The array consists of only 3 distinct integers 0, 1, 2.
2. The array is non-empty.

Given a singly linked list of 'N' nodes. The objective is to determine the middle node of a singly linked list. However, if the list has an even number of nodes, we return the second middle node.

Note:

1. If the list is empty, the function immediately returns None because there is no middle node to find.
2. If the list has only one node, then the only node in the list is trivially the middle node, and the function returns that node.

You are given a Singly Linked List of integers. Return true if it has a cycle, else return false.

A cycle occurs when a node's next points back to a previous node in the list.

Example:

In the given linked list, there is a cycle, hence we return true.

Why Java is platform independent ?

Difference between Abstract classes and interface