import random
import time

def merge_sort(nums):
    length_of_nums = len(nums)
    
    if length_of_nums < 2:
        return nums

    split = int(length_of_nums / 2)    
    
    split_one = nums[0:split]
    split_two = nums[split:]
    
    sorted_left_side = merge_sort(split_one)
    sorted_right_side = merge_sort(split_two)
    
    return merge(sorted_left_side, sorted_right_side)


def merge(first, second):
    final = []
    i = 0
    j = 0

    while i < len(first) and j < len(second):
        if first[i] <= second[j]:
            final.append(first[i])
            i += 1

        else:
            final.append(second[j])
            j += 1
        
    if len(first) > 0:
        for item in first[i:]:
            final.append(item)
    if len(second) > 0:
        for item in second[j:]:
            final.append(item)
        
    return final

# Create a list of random numbers
# The size 80,000 is quite large for Bubble Sort
list_size = 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9
num_list = [random.randint(1, 99999) for _ in range(list_size)]

print(f"Sorting a list of {list_size} numbers using Merge Sort...")

# --- Start the timer (using perf_counter for better benchmarking) ---
start_time = time.perf_counter()

# --- Call the sorting function ---
sorted_list = merge_sort(num_list) # Store the result without printing immediately
# sorted_list = sorted(num_list)

# --- Stop the timer ---
end_time = time.perf_counter()

# --- Calculate and print elapsed time ---
elapsed_time = end_time - start_time
print(f"Elapsed time: {elapsed_time:.4f} seconds")

# --- Optional: Print a small portion of the sorted list to verify ---
print("First 10 elements of sorted list:", sorted_list[:10])
print("Last 10 elements of sorted list:", sorted_list[-10:])