Ruby on Rails Coding Interview Question: Find the Second Largest Number in an Array

Preparing for a Ruby on Rails coding interview may be a stressful commitment. With the correct information and practice, though, you can confidently demonstrate your skills and obtain your desired job. I present a detailed list of frequent Ruby on Rails coding interview questions in this blog article to help you prepare efficiently.

I encourage readers to practice coding challenges, review the Rails documentation, and seek additional resources to enhance their understanding of Ruby on Rails. Armed with this knowledge, you’ll be well-equipped to excel in Ruby on Rails coding interviews and secure your desired position in web development.

Question

Write a Ruby method to find the second-largest number in an array

Solution 1

def second_largest(arr)
  arr.max(2).min
end

puts second_largest([5, 8, 2, 9, 1]) #=> 8

• arr.max(2) is used to find the two largest numbers in the array. It returns an array containing the two maximum values from the original array. In this case, it would return [9, 8].
• .min is then called on the resulting array from step 1 to find the minimum value, which corresponds to the second largest number. In this case, it would return 8.
• Finally, puts second_largest([5, 8, 2, 9, 1]) calls the second_largest method with the array [5, 8, 2, 9, 1] and outputs the result, which is 8.

This approach takes advantage of the built-in methods max and min provided by Ruby. By finding the two maximum numbers and selecting the minimum of those two, we effectively obtain the second-largest number from the original array.

Time Complexity

• The method utilizes the built-in methods max and min to find the second-largest number in the arr array. The max method, with an argument of 2, identifies the two largest elements with a time complexity of O(n), where n is the size of the input array.
• The resulting array is then passed to the min method, which has a time complexity of O(2) or O(1) since it operates on a fixed-size array of 2 elements. As a result, the overall time complexity of the method is…