Sort two arrays Python Codewars

Task:

Description:

Give you two arrays arr1 and arr2. They have the same length(length>=2). The elements of two arrays always be integer.

Sort arr1 according to the ascending order of arr2; Sort arr2 according to the ascending order of arr1. Description is not easy to understand, for example:

arr1=[5,4,3,2,1], 
arr2=[6,5,7,8,9]

Let us try to sorting arr1. First, we need know the ascending order of arr2:

[5,6,7,8,9]

We can see, after sort arr2 to ascending order, some elements' index are changed:

unsort arr2      ascending order arr2
[6,5,7,8,9]--->      [5,6,7,8,9]

index0(6)  --->      index1
index1(5)  --->      index0
index2(7)            index2(no change)
index3(8)            index3(no change)
index4(9)            index4(no change)

So, wo need according to these changes to sorting arr1:

unsort arr1          sorted arr1
[5,4,3,2,1]--->      [4,5,3,2,1]

index0(5)  --->      index1
index1(4)  --->      index0
index2(3)            index2(no change)
index3(2)            index3(no change)
index4(1)            index4(no change)

So: sorted arr1= [4,5,3,2,1]

And then, we sorting arr2 with the same process:

unsort arr1      ascending order arr1
[5,4,3,2,1]--->      [1,2,3,4,5]

index0(5)  --->      index4
index1(4)  --->      index3
index2(3)            index2(no change)
index3(2)  --->      index1
index4(1)  --->      index0

unsort arr2          sorted arr2
[6,5,7,8,9]--->      [9,8,7,5,6]

index0(6)  --->      index4
index1(5)  --->      index3
index2(7)            index2(no change)
index3(8)  --->      index1
index4(9)  --->      index0

So: sorted arr2= [9,8,7,5,6]

Finally, returns the sorted arrays by a 2D array: [sorted arr1, sorted arr2]

Note: In ascending order sorting process(not the final sort), if some elements have same value, sort them according to their index; You can modify the original array, but I advise you not to do that. ;-)

Some Examples and explain

sortArrays([5,4,3,2,1],[6,5,7,8,9]) should return
[[4,5,3,2,1],[9,8,7,5,6]]

sortArrays([2,1,3,4,5],[5,6,7,8,9]) should return
[[2,1,3,4,5],[6,5,7,8,9]]

sortArrays([5,6,9,2,6,5],[3,6,7,4,8,1]) should return
[[5,5,2,6,9,6],[4,3,1,6,8,7]]

Solution:

def sort_two_arrays(arr1, arr2):
    a1 = sorted((x, i) for i, x in enumerate(arr1))
    a2 = sorted((x, i) for i, x in enumerate(arr2))
    return [[arr1[i] for i in [x[1] for x in a2]], [arr2[i] for i in [x[1] for x in a1]]]

print(sort_two_arrays([5,4,3,2,1], [6,5,7,8,9]))

Sort two arrays Solutions | Codewars

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