Answers for "does .sort() use merge sort"

merge sort function

def merge_sort(arr):
    """Execute the merge sort algorithm"""
    if len(arr) > 1:
        # recursive case
        mid = len(arr) // 2 # find the midpoint of the array
        l = arr[:mid] # define the left half of the array
        r = arr[mid:] # define the right half of the array

        l = merge_sort(l) # sort the left half by calling this function
        r = merge_sort(r) # sort the right half by calling this function

        # now merge the two lists
        merged = [] # define an empty merged array
        while len(l) > 0 and len(r) > 0:
            # compare the heads of the left and right array
            if l[0] <= r[0]:
                # if the head of the left list is smaller than the head of the right list
                # pop the head of the left list and append it to the merged list
                merged.append(l.pop(0))
            else:
                # otherwise, pop the head of the right list and append that
                merged.append(r.pop(0))

        # add any elements remaining in the left or right list to the merged list
        merged = merged + l + r

        return merged
    else:
        # base case
        return arr

Merge_sort

def mergeSort(arr):
    if len(arr) > 1:
        mid = len(arr)//2
        L = arr[:mid]
        R = arr[mid:]
        mergeSort(L)
        mergeSort(R)
        i = j = k = 0
        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
        while i < len(L):
            arr[k] = L[i]
            i += 1
            k += 1
        while j < len(R):
            arr[k] = R[j]
            j += 1
            k += 1
def printList(arr):
    for i in range(len(arr)):
        print(arr[i], end=" ")
    print()
if __name__ == '__main__':
    arr = [12, 11, 13, 5, 6, 7]
    print("Given array is", end="\n")
    printList(arr)
    mergeSort(arr)
    print("Sorted array is: ", end="\n")
    printList(arr)