COSC 511 In class assignment  9/23            Individual work only!

1. Given postfix expression, 1 2 3 4 + - *, what is the corresponding
binary tree (expression tree)?


2. Given binary (expression tree)
  +
     *
         a
         b
     /
         c
         -
            d
            e
           
what is infix expression?


Graph G:
   |  a   b   c   d   e   f
---|-----------------------
a  |  1   1   1   1
   |
b  |  1   1
   |
c  |  1       1
   |
d  |  1           1   1   1
   | 
e  |              1   1   1
   |
f  |              1   1   1


3. Given graph G, provide a breadth-first traversal starting with e?


4. Given graph G, provide a depth-first traversal starting with e?


5. Here is pseudo-code for binary tree traversal.  Is it infix, postfix or 
prefix?

traversal (node) {
  if (node is null) return;
  if (node is leaf) {
                     output (node.value);
                     return;
                    }
  traversal (node.right);
  traversal (node.left);
  output(node.value);
  }
  

6. The pseudocode given in 5 has the left and right subtrees visited in reverse
order.  What would be the output of the code in #5 if run on the binary tree
given in #2.