Problem
1. Create a binary heap with a limited heap size. In other words, the heap only keeps track of the n most important items. If the heap grows in size to more than n items the least important item is dropped.
2. Clean up the print_exp function so that it does not include an ‘extra' set of parentheses around each number.
3. Using the build_heap method, write a sorting function that can sort a list in (𝑛 log 𝑛) time.