(b) Suppose there are n numbers in the binary search tree, what is the worst-case time complexity of searching a number in it? Please answer with big-O notation and give an example when such worst case happens. (8%)

(b) Consider another sum-of-subsets problem with n = 4, W =13, and w1= 3, w2 = 4, w3 = 5, w4 = 6. Use a similar tree as above, give a strategy to avoid searching every possible traversing route in the tree, and show that it can still get to the correct answer. (10%)