*4. Knapsack Problem. A hiker has a 5-ft3 backpack and needs to decide on the most valuable items to take on the hiking trip. There are three items from which to choose. Their volumes are 2, 3, and 4 ft3, and the hiker estimates their associated values on a scale from oto 100 as 30,50, and 70, respectively. Express the problem as longest-route network, and find the optimal solution. (Hint: A node in the network may be defined as [i, v], where i is the item number considered for packing, and v is the volume remaining immediately before a decision is made on i.)