3. (16%) Suppose that n = 3, W = 6, and w1= 2, w2 = 4, W3 = 5, we can construct a tree as follows:
申論題內容
(a) This tree can be used to find out all subsets of {W1, W2, W3}that sum to W(the sum-of-subscts problem); please explain what this tree represents and how it works to solve this problem. (6%)