1. (a) (5 points) Illustrate the execution of the heap-sort algorithm on the following sequence: (2, 5, 16, 4, 10, 23, 39, 18, 26, 15). Show the contents of the heap and the sequence at each step of the algorithm. Indicate upheap or downheap bubbling where appropriate. b) (5 points) Ilustrate the execution of the bottom-up construction of a heap (like in Figure 2.49) on the following sequence: (2, 5, 16, 4, 10, 23, 39, 18, 26, 15, 7, 9, 30, 31, 40)