Backend Developer

Which of the following is the property of transaction that protects data from system failure?

Which normalization form is based on the transitive dependency?

During transaction before commit which of the following statement is done automatically in case of shutdown?

Which of the following is known as minimal super key?

How many levels are there in architecture of database?

A doubly-linked list is a data structure that consists of sequentially linked nodes, and the nodes have reference to both the previous and the next nodes in the sequence of nodes.

You are given a sorted doubly linked list of size 'n', consisting of distinct positive integers, and a number 'k'.

Find out all the pairs in the doubly linked list with sum equal to 'k'.

Example :

Input: Linked List: 1 <-> 2 <-> 3 <-> 4 <-> 9 and 'k' = 5

Output: (1, 4) and (2, 3)

Explanation: There are 2 pairs in the linked list having sum 'k' = 5.

You are given a string 'STR' of lowercase English alphabets. You need to find the repeated character present first in the string.

Example:

If the string is: “abccba”, then the first repeated character is ‘c’, but the repeated character that is present first in the string is ‘a’. You need to print ‘a’.

Note:

Keep in mind that you need to print the repeated character that is present first in the string and not the first repeating character.

Given two integers, ‘N’ and ‘M’, your task is to find the sum of Fibonacci numbers between ‘fib(N)’ and ‘fib(M)’ where ‘fib(N)’ represents the Nth Fibonacci number and ‘fib(M)’ represents the Mth Fibonacci number. The sum is given by sum(N, M) = fib(N) + fib(N+1) + fib(N+2) … fib(M). Since the answer could be large, so you have to return the sum modulo 10^9 + 7.

The fibonacci relation is given by:

fib(0) = 0 
fib(1) = 1
fib(n) = fib(n-1) + fib(n-2), n >= 2, where fib(n) represents the nth fibonacci number.

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.