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April 19, 2018 13:11
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dynamic programming code
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"It's a reworked version of Problem 14 that you find here: http://interactivepython.org/runestone/static/pythonds/Recursion/pythondsProgrammingExercises.html" | |
dizio_1 = { (2,2): 1, (3,4): 2, (4,6): 3, (5,7): 4, (9,10): 5, (9,11): 6, (13,15): 7, (16,19): 8, \ | |
(25,37): 9, (35,45):10 } | |
def createTab ( _Dict ): #create the graphic tab | |
dizio = _Dict | |
print('','Item', 'Weight', 'Value','\n', sep=" " ) | |
for key in dizio: | |
spazio = " " | |
print(" ", str(dizio[key]).ljust(len(spazio)), str(key[0]).ljust(len(spazio)), str(key[1])) | |
print() | |
createTab(dizio_1) | |
print('\n\n') | |
def bottomUpDynamic(dizio, weightAvail): | |
weightValues = dict(dizio.keys()) | |
r = [0] * weightAvail # the list where we will put the maximum value for each bearable weight | |
s = [0] * weightAvail # the list where the each element represents the weight "taken" | |
q = 0 | |
for j in range(2, weightAvail+1): | |
for i in [c for c in weightValues if c <= j]: | |
if q < weightValues[i] + r[j-1 - i]: | |
q = weightValues[i] + r[j-1 - i] | |
s[j-1] = i | |
r[j-1] = q | |
return r,s | |
Bearable_weight = 38 | |
r,s = bottomUpDynamic(dizio_1, Bearable_weight) | |
for g,k in enumerate(r): | |
if g+1 == Bearable_weight: | |
print('Bearable weight by the knapsack: {} => Maximum profit obtainable : {}'.format(g+1,k)) | |
print('\n/-----/\n') | |
from itertools import groupby | |
def printCombination(weightAvail): | |
print("Items in the knapsack: \n") | |
global s, dizio_1 | |
dizio = { x[0]: dizio_1[x] for x in dizio_1 } | |
new = [] | |
while weightAvail > 0: | |
if s[weightAvail-1] in dizio: # this condition is necessary because when a weight is in | |
# our initial dizio_1 but it is "not taken" it generates 0 as value in s, and so it | |
# doesn't exist anymore in dizio and we must take one step back in the iteration. | |
new.append(dizio[s[weightAvail-1]]) | |
weightAvail -= s[weightAvail-1] | |
else: | |
weightAvail -= 1 | |
for s,g in groupby(new): | |
print("Item {} taken {} times ".format(s, len(list(g)))) | |
printCombination(Bearable_weight) |
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