print "\n\n"
# Get the capacity for the bins from the user
cap = binModule.getCap()
# Get the items from the user
items = binModule.getItems()
maxBins = len(items)
minBins = int(math.ceil(sum(items) / cap))
bins = []
print "Your items are:", items, "\nYour bins have capacity", cap, "\n"
print "MIN number of bins feasible:", int(
minBins), "\nMAX number of bins (i.e. # items)", maxBins, "\n\n"
bins.append(Bin(cap, [])) # we need at least one bin to begin
t1 = clock()
for item in items:
# Add the item to the first bin that can hold it
# If no bin can hold it, make a new bin
if item > cap:
print "SOME ITEM WON'T EVEN FIT IN ITS OWN BIN! ABORTING"
sys.exit()
for xBin in bins:
if xBin.capacity - sum(xBin.contents) >= item:
xBin.add(item)
break
if bins.index(xBin) == len(bins) - 1:
bins.append(Bin(cap, []))
# Make sure no item is too large
checkInput(allItems)
# Check if we're in the case where all items need their own bins
if easyCase(allItems):
print "Easy case"
curMin = len(allItems)
for item in allItems:
config.append([item])
else:
# Iterate through the permutations of the items
for x in itertools.permutations(items):
bins = [] # Clear the list of bins out after each new permuatation
Binny = Bin(cap, [bigItem]) # A bin to begin your packing
bins.append(Binny)
# Iterate through each item in this permutation
for item in x:
# Don't bother finding out how to fit items if it's not better
if len(bins) >= curMin:
break
# Still room in this bin?
if Binny.free_capacity() >= item:
Binny.add(item)
# No...we need a fresh bin
else:
Binny = Bin(cap, [])
Binny.add(item)
bins.append(Binny)
# We've put all the items in the perm into bins...
def solve_problem(cap, allItems):
def easyCase(aList):
for item in aList:
if item < cap/2:
return False
return True
def checkInput(aList):
for item in aList:
if item > cap:
print("SOME ITEM WON'T EVEN FIT IN ITS OWN BIN! ABORTING")
sys.exit()
print("\n\n")
# Get the capacity for the bins from the user
items = sorted(allItems)
bigItem = items.pop() # We can reduce time by a factor of 2 by always putting the same item in bin0
maxBins = len(allItems)
minBins = int(math.ceil(sum(allItems)/cap))
curMin = maxBins + 1
config = []
print("Your items are:", allItems, "\nYour bins have capacity", cap, "\n")
print("MIN number of bins feasible:", int(minBins), "\nMAX number of bins (i.e. # items)", maxBins, "\n\n")
# Begin timing
t1 = clock()
# Make sure no item is too large
checkInput(allItems)
# Check if we're in the case where all items need their own bins
if easyCase(allItems):
print("Easy case")
curMin = len(allItems)
for item in allItems:
config.append([item])
else:
# Iterate through the permutations of the items
for x in itertools.permutations(items):
bins = [] # Clear the list of bins out after each new permuatation
Binny = Bin(cap, [bigItem]) # A bin to begin your packing
bins.append(Binny)
# Iterate through each item in this permutation
for item in x:
# Don't bother finding out how to fit items if it's not better
if len(bins) >= curMin:
break
# Still room in this bin?
if Binny.capacity - sum(Binny.contents) >= item:
Binny.add(item)
# No...we need a fresh bin
else:
Binny = Bin(cap, [])
Binny.add(item)
bins.append(Binny)
# We've put all the items in the perm into bins...
# If we've reached a new minimum of bins used, save the
# minimum and keep a "proof" copy of the configuration that worked
if len(bins) < curMin:
curMin = len(bins)
config = copy.deepcopy(bins)
# If we used the true minimum number of bins, we're definitely done
if len(bins) == minBins:
break
# End timing
t2 = clock()
print(t2-t1)
# Put the item we removed back in so it looks pretty
items.append(bigItem)
print("True Bin Packing for", items, "with capacity", cap, "used", curMin, "bins")
print("A configuration that worked was:", config)
return config
# Make sure no item is too large checkInput(allItems) # Check if we're in the case where all items need their own bins if easyCase(allItems): print "Easy case" curMin = len(allItems) for item in allItems: config.append([item]) else: # Iterate through the permutations of the items for x in itertools.permutations(items): bins = [] # Clear the list of bins out after each new permuatation Binny = Bin(cap, [bigItem]) # A bin to begin your packing bins.append(Binny) # Iterate through each item in this permutation for item in x: # Don't bother finding out how to fit items if it's not better if len(bins) >= curMin: break # Still room in this bin? if Binny.free_capacity() >= item: Binny.add(item) # No...we need a fresh bin else: Binny = Bin(cap, []) Binny.add(item) bins.append(Binny) # We've put all the items in the perm into bins...
# Make sure no item is too large checkInput(allItems) # Check if we're in the case where all items need their own bins if easyCase(allItems): print "Easy case" curMin = len(allItems) for item in allItems: config.append([item]) else: # Iterate through the permutations of the items for x in itertools.permutations(items): bins = [] # Clear the list of bins out after each new permuatation Binny = Bin(cap, [bigItem]) # A bin to begin your packing bins.append(Binny) # Iterate through each item in this permutation for item in x: # Don't bother finding out how to fit items if it's not better if len(bins) >= curMin: break # Still room in this bin? if Binny.capacity - sum(Binny.contents) >= item: Binny.add(item) # No...we need a fresh bin else: Binny = Bin(cap, []) Binny.add(item) bins.append(Binny) # We've put all the items in the perm into bins...
