In this challenge, you will implement a function to calculate the factorial of a given non-negative integer. The factorial of a number n (denoted as n!) is the product of all positive integers less than or equal to n. For example, the factorial of 5 is 5! = 5 * 4 * 3 * 2 * 1 = 120.

Factorials grow very quickly, so it is important to handle large numbers appropriately. Rust's standard library provides the u128 type, which can handle very large integers. Your task is to implement a function that calculates the factorial of a given u32 number and returns the result as a u128.

Your task

Implement a function factorial(n: u32) -> u128 that calculates the factorial of the given non-negative integer n. Use early returns to handle the base case when n is 0, since 0! is defined as 1. For other values of n, use a loop to calculate the factorial.

Requirements

• The function should take a single argument n of type u32 and return a u128.
• Use early returns to handle the case when n is 0.
• For other values of n, use a loop to calculate the factorial.

Example

let result = factorial(5);
assert_eq!(result, 120);

let result = factorial(10);
assert_eq!(result, 3628800);

let result = factorial(0);
assert_eq!(result, 1);

Hints

• Remember that Rust has a u128 type which can hold very large numbers. This will be useful for calculating large factorials.
• Use the return statement to handle the base case of 0!.
• A for loop or while loop can be used to multiply the numbers from 1 to n.
• Consider using an iterative approach rather than a recursive one to avoid potential stack overflow issues for large n.