TASK #1 - Binary Tree Depth

You are given binary tree.

Write a script to find the minimum depth.

The minimum depth is the number of nodes from the root to the nearest
leaf node (node without any children).

Example 1:

  Input: '1 | 2 3 | 4 5'

                1
               / \
              2   3
             / \
            4   5

  Output: 2

Example 2:

  Input: '1 | 2 3 | 4 *  * 5 | * 6'

                1
               / \
              2   3
             /     \
            4       5
             \
              6
  Output: 3

MY NOTES: well, if I built a binary tree from the input, it would be quite
simple to find the minimum depth.  But there must be a way to solve the
problem using only the input syntax.  Something like: split into rows on '|'.
Each row has 2 * (rowno-1) elements (starting at row 1).  If a row hasn't
got that many elements, pad it with '*'s.  Now, find the first non-full row,
ie. with one or more '*'s.  Take the row a pair of elements at a time. If
any pair are both '*'s, then the min depth is rowno-1.  Otherwise proceed
to the next row, and keep going down the rows.


TASK #2 - Rob The House

You are planning to rob a row of houses, always starting with the first
and moving in the same direction. However, you can't rob two adjacent
houses.

Write a script to find the highest possible gain that can be achieved.

Example 1:

  Input: @valuables = (2, 4, 5);
  Output: 7

If we rob house 0 we get 2 and then the only house we can rob is house
2 where we have 5.  So the total valuables in this case is (2 + 5) = 7.


Example 2:

  Input: @valuables = (4, 2, 3, 6, 5, 3);
  Output: 13

The best choice would be to first rob house 0 then rob house 3 then finally
house 5.  This would give us 4 + 6 + 3 =13.


MY NOTES: Hmm.. some sort of recursive "find all paths" method.
It always helps to pick the right function purpose and name.
I think the recursive function we need is: 
my $maxvaluables = maxrobbery( startpos ), invoked as my $max=maxrobbery(0)?