def __init__(self, sequence):
# check that sequence is an iterable type
try:
_ = [x for x in sequence]
except:
raise TypeError('Expected sequence to be iterable.')
# check that the sequence contains only integers
for x in sequence:
if not float(x).is_integer():
raise TypeError('Sequence must contain only integers.')
# make sure all entries in the sequence are of type int and sort in non-increasing order
S = [int(x) for x in sequence]
S.sort(reverse=True)
process_sequence = [
list(S)
] # keeps track of resulting sequences at each step
elim_sequence = [
] # keeps track of the elements eliminated at each step
while S[0] > 0 and S[0] < len(S):
# so long as the largest element d of the sequence is positive, remove d from the sequence and subtract 1 from the next d elements
d = S.pop(0)
for i in range(d):
S[i] = S[i] - 1
S.sort(reverse=True)
# append the resulting sequence to the process sequence
process_sequence.append(list(S))
# append the removed element to the elimination sequence
elim_sequence.append(d)
# finally, append the 0s in the last step of the Havel Hakimi process to the elimination sequence
if contains_only_zeros(process_sequence[-1]):
elim_sequence.extend(S)
# set class attributes
self.process = process_sequence
self.eliminationSequence = elim_sequence
def is_graphic(self):
"""Return whether or not the initial sequence is graphic.
Returns
-------
bool
True if the initial sequence is graphic. False otherwise.
"""
return contains_only_zeros(self.process[-1])
def __init__(self, lSequence):
lSequence.sort(reverse=True)
process_sequence = [
list(lSequence)
] # keeps track of resulting sequences at each step
elim_sequence = [
] # keeps track of the elements eliminated at each step
while lSequence[0] > 0 and lSequence[0] < len(lSequence):
# so long as the largest element d of the sequence is positive, remove d from the sequence and subtract 1 from the next d elements
d = lSequence.pop(0)
for i in range(d):
lSequence[i] = lSequence[i] - 1
lSequence.sort(reverse=True)
# append the resulting sequence to the process sequence
process_sequence.append(list(lSequence))
# append the removed element to the elimination sequence
elim_sequence.append(d)
# finally, append the 0s in the last step of the Havel Hakimi process to the elimination sequence
if contains_only_zeros(process_sequence[-1]):
elim_sequence.extend(lSequence)
# set class attributes
self.process = process_sequence
self.eliminationSequence = elim_sequence
def is_graphic(self):
return contains_only_zeros(self.process[-1])