How would you define an algorithm if you had to do it from scratch?

Describe the algorithm to solve this problem.

What do you mean when you refer to an algorithm's "worst case efficiency"?

Suppose an algorithm requires 2n steps to complete a task for an input of size n. If the size of the input is doubled, what happens to the number of steps? The number of steps for the larger input is equal to the number of steps for the original input. The number of steps for the larger input is twice the number of steps for the original input. The number of steps for the larger input is four times the number of steps for the original input. The number of steps for the larger input is the square of the number of steps for the original input. The number of steps for the larger input is more than the number of steps for the original input, but is none of the above.

kindly solve this problem using python

I need to write an algorithm pseudocode that sorts a list of n elements in non-increasing order by finding the largest and smallest elements and exchanging those elements with the elements in the first and last positions. Then the size of the list is reduced by 2, excluding the two elements that are already in the proper positions, and the process is repeated on the remaining part of the list until the entire list is sorted. I also need to analyze the algorithm and show the results using order notation. I was trying to use arguments but I got stuck.