1.4 In a min-heap with n > 0 nodes, how many are leaves? Write one mathematical formula (not a C0 expression) that expresses the number of leaves regardless of whether n is even or odd. You may use [x] to round x down and [x] to round up. 1.5 Suppose a sequence of n elements are inserted into a priority queue so that the priority of each element inserted is strictly decreasing. Afterward, the elements are removed one at a time based on priority. What common data structure does this priority queue implement? If the priorities are strictly increasing instead, what common data structure does this priority queue implement?