Hacktoberfestmine/Merge Sort program in python at main · pythonites/Hacktoberfestmine · GitHub

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def merge(arr, l, m, r):

    n1 = m - l + 1

    n2 = r - m


    L = [0] * (n1)

    R = [0] * (n2)


    for i in range(0, n1):

        L[i] = arr[l + i]


    for j in range(0, n2):

        R[j] = arr[m + 1 + j]


    i = 0

    j = 0

    k = l


    while i < n1 and j < n2:

        if L[i] <= R[j]:

            arr[k] = L[i]

            i += 1

        else:

            arr[k] = R[j]

            j += 1

        k += 1


    while i < n1:

        arr[k] = L[i]

        i += 1

        k += 1


    while j < n2:

        arr[k] = R[j]

        j += 1

        k += 1

# l is for left index and r is right index of the
# sub-array of arr to be sorted


def mergeSort(arr, l, r):

    if l < r:


        m = l+(r-l)//2


        mergeSort(arr, l, m)

        mergeSort(arr, m+1, r)

        merge(arr, l, m, r)


arr = [12, 11, 13, 8, 9, 3]

n = len(arr)

print("Given array is GIVEN BELOW")

for i in range(n):

    print("%d" % arr[i]),


mergeSort(arr, 0, n-1)

print("\n\nSorted array is GIVEN BELOW")

for i in range(n):

    print("%d" % arr[i]),