2. [0/1 Knapsack] Consider the knapsack problem discussed in this section. We add the requirement that xi=1 or xi=0,1in; that is, an object is either included or not included into the knapsack. We wish to solve the problem max1npixisubjectto1nwiximandxi=0or1,1in One greedy strategy is to consider the objects in order of nonincreasing density pi/wi and add the object into the knapsack if it.fits. Show that this strategy doesn't necessarily yield an optimal solution