Given an array of positive integers, rearrange the elements such that the resulting number formed by concatenating the elements is the largest possible number.

Function Signature:

from typing import List

def rearrange_array(arr: List[int]) -> int:
    """
    Rearrange the elements of the array to form the largest possible number.

    Parameters:
    - arr: A list of positive integers.

    Returns:
    - int: The largest possible number formed by rearranging the elements.
    """
    # Your code here

Example:

arr = [10, 7, 76, 415]
result = rearrange_array(arr)
print(result)  # Output should be 77641510

arr = [3, 30, 34, 5, 9]
result = rearrange_array(arr)
print(result)  # Output should be 9534330

arr = [1, 2, 3, 4, 5]
result = rearrange_array(arr)
print(result)  # Output should be 54321

Note:

  • The input array may contain duplicate elements.
  • The rearranged number should not have leading zeroes.

Instructions:

  • Implement the rearrange_array function to solve the problem.
  • Use Python for your implementation.
  • Provide clear comments in your code to explain the logic.
  • Discuss the time and space complexity of your solution.

As always, we’ll share our solution to this problem tomorrow. Stay tuned 😊