mergesorting.py

def mergesort(A, left, right):
    if left < right:
        mid = (left + right) // 2
        mergesort(A, left, mid)
        mergesort(A, mid + 1, right)
        merge(A, left, mid, right)


def merge(A, left, mid, right):
    i = left
    j = mid + 1
    k = left
    B = [0] * (right + 1)

    while i <= mid and j <= right:
        if A[i] < A[j]:
            B[k] = A[i]
            i = i + 1
        else:
            B[k] = A[j]
            j = j + 1
        k = k + 1

    while i <= mid:
        B[k] = A[i]
        i = i + 1
        k = k + 1
    while j <= right:
        B[k] = A[j]
        j = j + 1
        k = k + 1

    for x in range(left, right + 1):
        A[x] = B[x]


A = []
v = int(input("Enter the size of an array : "))
for arr in range(v):
    print("Enter the element at index : ",arr)
    l = int(input())
    A.append(l)
print('Original Array:',A)
mergesort(A, 0, len(A) - 1)
print('Sorted Array:',A)