1. Suppose we have a list of items with prices {p,, p,, ...,p, }. The prices are not necessarily sorted. (a) Give an efficient algorithm that determines the most items that we can buy if we have M money. [Hint: it is a greedy algorithm.] (b) Argue that your greedy choice gives you an optimal choice. (c) What is the time complexity of your algorithm? (d) Explain what makes this problem different from the discrete (0/1) knapsack problem, which requires dynamic programming and doesn't have a greedy solution