MergeSort.py

def mergeSort(arr):
    if len(arr)>1:
        r=len(arr)//2
        leftArr = arr[:r]
        rightArr = arr[r:]
        mergeSort(leftArr)
        mergeSort(rightArr)
        i=j=k=0
        while i<len(leftArr) and j<len(rightArr):
            if leftArr[i]<rightArr[j]:
                arr[k]=leftArr[i]
                i+=1
            else:
                arr[k] = rightArr[j]
                j+=1
                k+=1
        while i<len(leftArr):
            arr[k] = leftArr[i]
            i+=1
            k+=1
        while j<len(rightArr):
            arr[k]=rightArr[j]
            j+=1
            k+=1
def display(arr):
    for i in range(len(arr)):
        print(arr[i],end='')
        print()

if __name__ == '__main__':
    arr = [6,5,12,10,9]
    print('Original array')
    display(arr)
    mergeSort(arr)
    print('Sorted array')
    display(arr)