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Unformatted text preview: ptimal for denominations 1, 6, and 10 Via induction, and on board --> 14 Knapsack Algorithm 15 Knapsack Problems Inputs: n items, each with a weight wi and a value vi
capacity of the knapsack, C Output: Fractions for each of the n items, xi Chosen to maximize total profit but not to exceed
knapsack capacity 16 Two Types of Knapsack Problem 0/1 knapsack problem Greedy approach does not produce optimal solutions Each item is discrete. Must choose all of it or none of
it. So each xi is 0 or 1
But another approach, dynamic programming, does Continuous knapsack problem Can pick up fractions of each item The correct selection function yields a greedy algorithm
that produces optimal results 17 Greedy Rule for Knapsack? Build up a partial solution by choosing xi for one item
until knapsack is full (or no more items). Which item
to choose? There are several choices. Pick one and try on this: n = 3, C = 20 weights = (18, 15, 10) values = (25, 24, 15) What answer do you get? The optimal answer is: (0, 1, 0.5), total=31.5 18 Can you verify this? Possible Greedy Rules for Kn...
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- Spring '10