All integers are different. Create a sorted list of 27 elements. Think about this more generally. Let A be a sorted list of n elements, let B be a sorted list of m elements, and let C be an unsorted list of k elements. Question 2 Recurrences, trees.
Solution Let h be the height of the tree.
Now take logarithms to the base 41. Question 3 Stacks, queues, algorithms. The postfix expression is given to you as a queue Q of elements. We will stick all elements and partial infix subexpressions in queues. The JOIN operation puts the parentheses in the right places so that operator precedence is a non-issue.