1 files changed, 59 insertions, 33 deletions
diff --git a/challenge-151/duncan-c-white/README b/challenge-151/duncan-c-white/README
index 4c7c2d807d..b4889e4611 100644
--- a/challenge-151/duncan-c-white/README
+++ b/challenge-151/duncan-c-white/README
@@ -1,48 +1,74 @@
-TASK #1 - Fibonacci Words
+TASK #1 - Binary Tree Depth
 
-You are given two strings having same number of digits, $a and $b.
+You are given binary tree.
 
-Write a script to generate Fibonacci Words by concatenation of the
-previous two strings. Finally print 51st digit of the first term having
-at least 51 digits.
+Write a script to find the minimum depth.
 
-Example:
+The minimum depth is the number of nodes from the root to the nearest
+leaf node (node without any children).
 
-    Input: $a = '1234' $b = '5678'
-    Output: 7
+Example 1:
 
-    Fibonacci Words:
+  Input: '1 | 2 3 | 4 5'
 
-    '1234'
-    '5678'
-    '12345678'
-    '567812345678'
-    '12345678567812345678'
-    '56781234567812345678567812345678'
-    '1234567856781234567856781234567812345678567812345678'
+                1
+               / \
+              2   3
+             / \
+            4   5
 
-    The 51st digit in the first term having at least 51 digits
-    '1234567856781234567856781234567812345678567812345678' is 7.
+  Output: 2
 
-MY NOTES: Pretty easy.  Fibonacci words == append two previous strings.
-Use -d (debug mode) to see all the above explanatory info.
+Example 2:
 
+  Input: '1 | 2 3 | 4 *  * 5 | * 6'
 
-TASK #2 - Square-free Integer
+                1
+               / \
+              2   3
+             /     \
+            4       5
+             \
+              6
+  Output: 3
 
-Write a script to generate all square-free integers <= 500.
+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.
 
-In mathematics, a square-free integer (or squarefree integer) is an
-integer which is divisible by no perfect square other than 1. That is,
-its prime factorization has exactly one factor for each prime that
-appears in it. For example, 10 = 2 * 5 is square-free, but 18 = 2 *
-3 * 3 is not, because 18 is divisible by 9 = 3**2.
 
-Example
+TASK #2 - Rob The House
 
-The smallest positive square-free integers are
-    1, 2, 3, 5, 6, 7, 10, 11, 13, 14, 15, 17, 19, 21, 22, 23, 26, 29, 30, ...
+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.
 
-MY NOTES: also pretty easy.  The second definition above suggests using prime
-numbers, which is easy enough, especially as I have a prime generating module,
-but actually it's simpler to do it without primes as the first definition hints.
+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)?