def testInsertion(n, mn, mx):
L = random.sample(range(mn, mx), n)
Sorts.insertion(L)
for i in range(len(L) - 2):
if (L[i] > L[i + 1]):
return False
return True
def dual_pivot(T,left=0,right=None,randomize=True,threshold=16,subsort=insertion):
if right == None:
right = len(T) - 1
# the lower limit of 17 is according to the paper
if right - left < threshold:
Sorts.insertion(T,left,right)
return
if randomize:
pivot1idx = random.randrange(left,right+1)
T[left],T[pivot1idx] = T[pivot1idx],T[left]
pivot2idx = random.randrange(left+1,right+1)
T[right],T[pivot2idx] = T[pivot2idx],T[right]
#make sure left pivot is smaller
if T[left] > T[right]:
T[left],T[right] = T[right],T[left]
P1, P2 = T[left], T[right]
K = L = left + 1
G = right - 1
while K <= G:
if T[K] < P1:
T[L],T[K] = T[K],T[L]
L += 1
K += 1
elif T[K] > P2:
T[K],T[G] = T[G],T[K]
# we haven't examined the value that was at T[G]
# K is not advanced, so we will check it next
G -= 1
else:
K += 1
#swap pivots into final positions
T[left],T[L-1] = T[L-1],T[left]
T[right],T[G+1] = T[G+1],T[right]
dual_pivot(T,left,L-2,randomize,threshold,subsort)
dual_pivot(T,L,G,randomize,threshold,subsort)
dual_pivot(T,G+2,right,randomize,threshold,subsort)
def sort(self,items):
Sorts.insertion(items)
