|
| 1 | +from itertools import combinations |
| 2 | + |
| 3 | +def brute_force(number, capacity, weight_cost): |
| 4 | + best_cost = None |
| 5 | + best_combination = [] |
| 6 | + |
| 7 | + for i in range(1,number+1): |
| 8 | + for comb in combinations(weight_cost, i): #generate combinations of length from 1 to n |
| 9 | + temp = list(combinations(weight_cost, i)) |
| 10 | + weight = sum(wc[0] for wc in comb) #Sum of all weights in combination |
| 11 | + cost = sum(wc[1] for wc in comb) #Sum of all costs in combination |
| 12 | + temp_index = [] |
| 13 | + for item in comb: |
| 14 | + temp_index.append(weight_cost.index(item)+1) |
| 15 | + print('Combination: {} Weight = {} Cost = {}'.format(temp_index, weight, cost)) |
| 16 | + if(best_cost is None or best_cost < cost) and weight <= capacity: #If best_cost is less, reinitialize the Knapsack |
| 17 | + best_cost = cost |
| 18 | + best_combination = [0]* number #Assign 0 to full array |
| 19 | + for wc in comb: |
| 20 | + best_combination[weight_cost.index(wc)] = 1 #Set the value to 1 which we want in KnapSack. |
| 21 | + return best_cost, best_combination |
| 22 | + |
| 23 | +n = int(input('Enter number of elements in KnapSack: ')) |
| 24 | +capacity = int(input('Enter capacity of KnapSack: ')) |
| 25 | + |
| 26 | +weight_cost = [] |
| 27 | + |
| 28 | +for i in range(n): |
| 29 | + weight = int(input('Enter weight of element {}: '.format(i+1))) |
| 30 | + cost = int(input('Enter cost of element {}: '.format(i+1))) |
| 31 | + weight_cost.append((weight, cost)) |
| 32 | + |
| 33 | +best_cost, best_combination = brute_force(n, capacity, weight_cost) |
| 34 | + |
| 35 | +print('The best cost obtained is: {}'.format(best_cost)) |
| 36 | + |
| 37 | +print('The corresponding combination is: ') |
| 38 | +print(best_combination) |
| 39 | +element_list = [] |
| 40 | +for i in range(len(best_combination)): |
| 41 | + if best_combination[i] == 1: |
| 42 | + element_list.append(i+1) |
| 43 | + |
| 44 | +print('The selected elements are: ') |
| 45 | +print(element_list) |
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