SDE - 1

You are given an array A of length N, where N is always an odd integer. There are (N-1)/2 elements in the array that occur twice and one element which occurs once.

Your task is to find the only element that occurs once in the array.

Note: There are (N-1)/2+1 elements that are unique in the array.

Example:

Consider the array be 1,6,4,6,2,4,2
The integers 2, 4, 6 occur twice and only the integer 1 occurs once. 

Ninja has been given an array/list of integers ‘ARR’ of size ‘N’. Ninja has to find the greatest number present in the ‘ARR’ such that this number is also equal to the product of the two elements present in the ‘ARR’.

Note:

1. The pair should be from different indices. 
2. If no such number is present in the ‘ARR’, then return -1.

A thief is robbing a store and can carry a maximal weight of W into his knapsack. There are N items and the ith item weighs wi and is of value vi. Considering the constraints of the maximum weight that a knapsack can carry, you have to find and return the maximum value that a thief can generate by stealing items.

You are given an array 'a' of size 'n'.

Print the Next Greater Element(NGE) for every element.

The Next Greater Element for an element 'x' is the first element on the right side of 'x' in the array, which is greater than 'x'.

If no greater elements exist to the right of 'x', consider the next greater element as -1.

For example:

Input: 'a' = [7, 12, 1, 20]

Output: NGE = [12, 20, 20, -1]

Explanation: For the given array,

- The next greater element for 7 is 12.

- The next greater element for 12 is 20. 

- The next greater element for 1 is 20. 

- There is no greater element for 20 on the right side. So we consider NGE as -1.

SQL Query for Second Highest Salary in an Emloyee table

TYPES OF KEYS
The interviewer draw a employee table in which Employee id , name and salary were mentioned 
I had to find the employee with second most highest salary

Normalization and All the normal forms

Write a Program to check whether the given number N is prime or not.

For a given number N check if it is prime or not. A prime number is a number that is only divisible by 1 and itself.