How do I implement merge sort in Python?

How do I implement merge sort in Python?

To implement merge sort in Python, you can follow these steps: 1. Divide the array into halves. 2. Recursively sort each half. 3. Merge the sorted halves.

Can you show me the code for that?

Sure! Here's a simple implementation:

def merge_sort(arr):
    if len(arr) > 1:
        mid = len(arr) // 2  # Finding the mid of the array
        L = arr[:mid]  # Dividing the elements into 2 halves
        R = arr[mid:]  

        merge_sort(L)  # Sorting the first half
        merge_sort(R)  # Sorting the second half

        i = j = k = 0

        # Copy data to temp arrays L[] and R[]
        while i < len(L) and j < len(R):
            if L[i] < R[j]:
                arr[k] = L[i]
                i += 1
            else:
                arr[k] = R[j]
                j += 1
            k += 1

        # Checking if any element was left
        while i < len(L):
            arr[k] = L[i]
            i += 1
            k += 1

        while j < len(R):
            arr[k] = R[j]
            j += 1
            k += 1

    return arr

What is the time complexity of merge sort?

The time complexity of merge sort is O(n log n) in the average and worst cases, making it efficient for large datasets.