SDE - 1

What is left join?

What are the different types of Joins in SQL?

You have been given an integer array/list 'ARR' of size 'N'. Write a solution to check if it could become non-decreasing by modifying at most 1 element.

We define an array as non-decreasing, if ARR[i] <= ARR[i + 1] holds for every i (0-based) such that (0 <= i <= N - 2).

Ninja started his new job as a manager in Railways Control Room. His task is to maintain the records of passengers traveling from one place to another. His task is to design a class that performs the following operations:

‘RAILWAY_SYSTEM’() is a function that initializes your data structures.

‘CHECK_IN’( ‘PASS_ID’,’ STATION’, TIME) represents that passenger with passenger ID ‘PASS_ID’ checks in at the station named ‘STATION’ at time ‘TIME’.

 A customer can only be checked into one place at a time.

‘CHECK_OUT’( ‘PASS_ID’,’ STATION’, TIME) represents that passenger with passenger ID ‘PASS_ID’ checks out at the station named ‘STATION’ at time ‘TIME’.

‘GET_AVERAGE_TIME(SOURCE, DEST) returns the average time it takes to travel from SOURCE to DEST.

The average time is computed from all the previous traveling times from SOURCE to DEST  that happened directly, meaning a check-in at SOURCE followed by a check out from DEST.

For Example

If the functions calls are as follows:
CHECK_IN(1,‘Delhi’,10)
CHECK_OUT(1,‘Noida’,20)
GET_AVERAGE(‘Delhi’,’ Noida’)
CHECK_IN(5,‘Delhi’,12)
CHECK_OUT(5,‘Noida’,17)
GET_AVERAGE(‘Delhi’,’ Noida’)

So, the answers for the GET_AVERAGE calls will be 10 and 7.5 respectively.
For the first call, there is only one trip between Delhi and Noida, so the average is 10.
For the second call, there are two between these stations, so the average is (10+5)/2 = 7.5

You are given a 0-indexed array ‘NUMS’ consisting of ‘N’ integers. Sort the array ‘NUMS’ in such a way that the first half of the array contains only odd numbers sorted in non-increasing order and the second half contains only even numbers sorted in non-decreasing order.

Example:

Input: ‘N’ = 4,  ‘NUMS’ = [2, 5, 3, 6] 

Output: [5, 3, 2, 6]

Sorting the odd numbers of the array ‘NUMS’ in non-increasing order, the result is 5, 3
Then, Sorting the even numbers in non-decreasing order, the result is 2, 6.
Since the final array should contain the odd numbers in non-increasing order in the first half and even numbers in non-decreasing order in the other half.
So, the final array is [5, 3, 2, 6].

Given two strings A and B, find if A is a subsequence of B.

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Get ad objects and create a domain platform get the all the install and uninstalls operations

Write SQL Query to get the details of the employees with the most number of absence?

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