Need help with quicksort

I know this is kind of stupid but I was trying to implement quicksort in Python and it runs into an infinite loop can anyone tell me what's wrong??The partition subroutine works perfectly....The error is in quicksort..Here's the code

     def QuickSort(A,p,r):
          if p < r:
              q = Partition(A,p,r)
              QuickSort(A,0,q)
              QuickSort(A,q+1,r)

    def Partition(A, l, r):
        p = A[l]
        i = l+1
        for j in range(l+1,r):
            if A[j] < p:
                A[j],A[i] = A[i],A[j]
                i += 1
        A[l],A[i-1] = A[i-1],A[l]
     return A.index(p)

#ComputerScience #HelpMe! #Help #brillianthelp #Pleasehelp

Easy Math Editor

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Comments

@Thaddeus Abiy @Ammar Fathin Sabili @Trevor B. Please help!!CS is one of the subjects that I study the most but failing such a trivial and known question today is driving me mad!

Eddie The Head - 7 years ago

@Chung Gene Keun

Eddie The Head - 7 years ago

def Quicksort(A,p,r):
    if p < r:
        q = Partition(A,p,r)
        Quicksort(A,p,q-1) #Mistake is here
        Quicksort(A,q+1,r)
    return A

I am reasonably sure that this is what would work. @josh silverman, can you confirm?

Trevor B. - 7 years ago

to start, your Quicksort doesn't return anything

Josh Silverman Staff - 7 years ago

Fixed!!Thanks a lot.....It feels so frustrated to do stupid mistakes on a known problem............

Eddie The Head - 7 years ago

Math	Appears as
Remember to wrap math in `\(` ... `\)` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$