Consider the author of the code you must modify as a resource. You may find yourself yelling at that resource or wishing that resource bodily harm by the end of this part of the assignment. This is normal, but do not act on such impulses. Instead, inform the resource of his/her transgressions:

• Lack of documentation
• Failure to honor the interface
• Lack of adequate testing
• Failure to provide for exceptional conditions

And now the mods:

1. The input format has been changed. In addition to what you have now, Each line will contain:
   • The character U or B to indicate unidirectional or bidirectional. Please don't send people down a one-way street the wrong way. Your TAs will not like that.
   • A number in the range of 1-4 to indicate the road type.
     • Type 1 is a major interstate;
     • Type 2 is a US highway;
     • Type 3 is a normal city street,
     • Type 4 is a dirt road with potholes, sharp/toxic objects from the town dump, and land mines stratigically placed to impede your progress.

     Why is this useful you ask? Well, the requests to your program, which used to contain only a starting and ending intersection, now also contains 4 numbers which indicate the requestor's average rate of travel (mph) on roads of type 1, 2, 3 and 4.

   • You will now receive a file (on cin) of requests for your program. Your program should behave as if each request were issued one per run. See the heap mod below for why this is interesting.
2. The heap has been identified as a serious bottleneck. It gets instantiated for each request, but it is always the same size: one heap slot per possible node. The heap must now be made a singleton object, appropriately reinitialized so you can perform multiple path computations more speedily.
3. Residents of Manhattan are irate because your path computations send them zig-zagging through the streets of NYC. You will fix this by introducing road-name-change-penalties in your shortest-path computations.

• Produce output that is more natural, telling people to turn right, left, etc.
• Introduce turn penalties: right turns are easier than left; going straight is the easiest thing to do; U-turns are fun but slow.
• Ellide straight segments, telling people what they pass on the way
• Pizza-dude problem (all combinations, travelling salesperson)
• Watch this space for more ideas