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@jrichter
Created March 3, 2013 06:29
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quicksort - gets it sorted but wastes time
def quicksortTest(A,p,r):
print A
if (p<r):
q = partition(A,p,r)
print "********************************************** q=, ", q, " r=", r
quicksortTest(A,q+1,r)
if (p==r):
print "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! p = r", p, r
q = partition(A,p,r)
quicksortTest(A,0,q-1)
#quicksortTest(A,p,q)
def partition(A, p, r):
x = A[p]
print "Pivot: ", x
i = p-1
j = r+1
while True:
while True:
j -= 1
print "working from the end, comparing", A[j], " and ", x
if (A[j]<=x):
print A[j], " <= ", x
break
while True:
i += 1
print "working from the beginning, comparing", A[i], " and ", x
if (A[i]>=x):
print A[i], " >= ", x
break
if (i<j):
print "Switching, ", A[i], " with ", A[j]
A[i], A[j] = A[j], A[i]
print A
else:
print i, " is not less than ", j
return j
def hoare(a, p, r):
x = a[p]
i, j = p-1, r+1
while True:
while True:
j -= 1
if a[j] <= x:
break
while True:
i += 1
if a[i] >= x:
break
if i < j:
print "Switching, ", a[i], " with ", a[j]
a[i], a[j] = a[j], a[i]
else:
return j
Array = [2,8,7,1,3,5,6,4]
p = 0
r = len(Array) - 1
print "*** START ***"
quicksortTest(Array,p,r)
print "*** END ***"
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