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Consider the procedure implementing quicksort: Quicksort(A,p,r){ if (p < r): q = Partition(A,p,r) Quicksort(A,p,q-1) Quicksort(A,q+1,r) }...

Consider the procedure implementing quicksort:

Quicksort(A,p,r){

if (p < r):

q = Partition(A,p,r)

Quicksort(A,p,q-1)

Quicksort(A,q+1,r)

}

If instead of calling Quicksort(A,p,q-1) , the call is Quicksort(A,p,q), What would be the consequence on correctness or running time when:

a) The array is already sorted

b) The array is filled with n copies of the same value

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Answer #1

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the correctness will be the same, it sorts the array but might fall in an infinite loop

an example: 1,2,3,4

the pivot is 4 and instead of the call p=0 r=3

we will q=3 so while the call Quicksort(A,p,q) the same array is called again

and again until it continues to be infinite

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