User Transaction Report for 2023
In the digital age, payment systems are essential for online transactions. For businesses managing these systems, understanding user activity is key to optimizing services and enhancing engagement.
A development team is tasked with creating a report that shows:
The total number of transactions made by each user.
The total sum of those transactions.
Analyzing t hese patterns will help identify highly active users and those who may need additional engagement.

Requirements
The output of the report should include the following columns:
- email: The email address of the user.
- total_transactions: The total number of transactions made by the user.
- total_amount: The total value of the transactions (rounded to two decimal places, including trailing
zeros if needed, e.g., 500.00).
The results should be sorted in ascending order by email.
Note:
Only include transactions that occurred in the year 2023.

Schema
Table: users
id (INT): The identifier of the user
email (VARCHAR(255)): The email address of the user

Table: transactions
user_id (INT): The reference to the user
amount (DECIMAL(5,2)): The amount of the transaction
created_at (VARCHAR(19)): The date and time of the transaction
Foreign Key: user_id references users(id) Show More

Roman Numerals

You are given an array of integers. Your task is to convert each integer into its Roman numeral equivalent.

The following table contains some reference values for converting between Arabic (standard integers) and Roman numerals:

Arabic - Roman
1 - I
4 - IV
5 - V
9 - IX
10 - X
40 - XL
50 - L
90 - XC
100 - C
400 - CD
500 - D
900 - CM
1000 - M

Example
Input: n umbers = [1, 49, 23]
Output: ["I", "XLIX", "XXIII"]

Explanation:

1 is "I"

49 is 40 + 9 → "XL" + "IX" = "XLIX"

23 is 10 + 10 + 3 → "X" + "X" + "III" = "XXIII"

Function Description
Complete the function romanizer in the editor below.

romanizer has the following parameters:
int numbers[n]: an array of integers

Returns
string[n]: an array of strings that represent the integers as their Roman numeral equivalents.

Constraints
1 ≤ n ≤ 1000
1 ≤ numbers[i] ≤ 1000 Show More

Hackerrank developers want to deploy an application on a set of exactly k servers with different vulnerabilities. They have an option to choose the k servers from a sequence of n servers where vulnerability[i] represents the vulnerability of the ith server.

The vulnerability of the chosen k servers is defined as the maximum vulnerability amongst any of the chosen servers. To avoid congestion, t hey would like to choose a subsequence of k servers such that no two adjacent servers are chosen as part of the k servers.

Given an array vulnerability and an integer k, find the minimum possible vulnerability of the chosen servers such that the above condition is respected.

Example
Given n = 4, k = 2 and vulnerability = [2, 3, 5, 9], only 3 subsequences of k = 2 non-adjacent servers exist:

[2, 5] - max = 5
[3, 9] - max = 9
[2, 9] - max = 9

Report 5 as the answer.

Function Description
Complete the function getMinVulnerability in the editor below.

getMinVulnerability has the following parameters:
int vulnerability[n]: An array of integers
int k: the length of the subsequences to form

Returns
int: the minimum value returned by the max function for all valid subsequences

Constraints
1 <= n <= 10^5
1 <= k <= (n + 1) / 2 Show More