Important:

• Please turn in a typed report -  handwritten material will not be graded.
• Due date: Feb. 1, 3:01pm, in class
  

For your information:

• Expected time effort for this homework: 6h-10h, broken down as follows:
• Q1: 30' to figure out the queries; 1-2 hours to load the data, debug the queries etc
  
• Q2: 1h to review the lecture notes; 2-3 hours to design the algorithm; 2-3 hours to implement and debug it.
• Points are in [bold pts] and add to 100.

Q1: SQL [30 pts]

1. [5 pts] list all the airports along with the number of outgoing flights, sorted in decreasing count order (that is, most busy airport first) 
2. [5 pts] list all the pairs of airports (a,b) , so that airport 'a' can reach airport 'b' within 2 hops or less.  A direct flight counts as 1 hop.
•  Eliminate duplicates;
  
• do not report self-pairs; 
• sort your answer in increasing alpha order (sort on 'from' first, then on 'to').
• Notice that not all flights have return flights.
3. [5 pts] report the number of pairs within 2 hops or less.
4. [10 pts] repeat,  for 3 hops or less: list all the (a,b) pairs of airports, so that 'a' can reach 'b' within 3 hops or less.
5. [5 pts] report the number of pairs within 3 hops or less.

• the resulting table [half of the points] and
• the corresponding SQL statement [rest half of the points].

Q2: K-d trees [70 pts]

• If the tree has fewer than k=10 nodes, then return all the nodes, with a warning: "only <number> nodes found".
  
• If you prefer some  language other than 'C' for the implementation, contact the instructor.

1. [30pts] a hard copy of your code
2. [35pts] a hard copy of  the output of your code, on the two included input scripts (2d-input.txt,3d-input.txt). In your output, keep only the lines that are the result of the query, to save paper. For your convenience, try 'make hw1'
3. [5pts] please e-mail your 'tar' file to the TA ('make kdtree.tar')