Upcoming Computer Science Competitions and Announcements for December 2008
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Get ready for an exciting month in computer science! Between December 5-8, participate in the USACO contests. Mark your calendars for the first ACSL competition happening on December 15. Two new competitions are also launched: the CML JAVA Computer Contest and the IPSC (Internet Problem Solving Contest). These contests feature team-based challenges designed to test your knowledge on topics like recursive functions, number systems, and data structures. Don’t miss out on enhancing your skills and competing with peers!
Upcoming Computer Science Competitions and Announcements for December 2008
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Presentation Transcript
Lynbrook Computer Science December 1, 2008
Announcements • USACO this week! (December 5-8) • First ACSL: Monday, December 15 • Two new competitions: • CML (Continental Mathematics League) JAVA Computer Contest • IPSC (Internet Problem Solving Contest)
CML (Continental Math League) JAVA Computer Contest • Done in JAVA • Done in teams • Written Contest • Based on AP Computer Science A/B curriculum • 25 Questions • 40 Minutes • Sometime between 4/20 and 5/1
IPSC (Internet Problem Solving Contest) • Online contest • Done in teams of 3 • 5 Hours • Any language can be used • Access to online resources is allowed • USACO-like problems
Tested Material on the ACSL What does this program do? Number Systems (different base operations) Recursive Functions (f(x) = f(x-1) + 1) Boolean Algebra (not A + B = …) Bit String Flicking (right shift, left shift) LISP Evaluation (ADD, SUB, etc.) Digital Electronics (AND, OR, XOR, NAND, NOR, XNOR) Prefix/Infix/Postfix Notation (+ 3 4) Data Structures (heaps, binary trees, stacks, etc.)
Recursive Functions • Find f(15) given the following: • f(x) = • 2 * f(x-3) – 4 [if x is composite] • x2 + x [if x is prime]
Solution • f(15) = 2 * f(12) – 4 • f(12) = 2 * f(9) – 4 • f(9) = 2 * f(6) – 4 • f(6) = 2 * f(3) – 4 • f(3) = 32 + 3 = 12 • Work backwards to get f(6) = 20, f(9) = 36, f(12) = 68, and f(15) = 132
LISP • Evaluate the following: • (CDR (CDR (CAR (CDR ‘(2 ((3 (4 5) 6) 7)))))) • Hint: • CDR ‘((x) y) = y • CAR ‘((x) y) = (x)
Solution • Work from the inside out: • (CDR '(2 ((3 (4 5) 6) 7))) = (((3 (4 5) 6) 7)) • (CAR '(((3 (4 5) 6) 7))) = ((3 (4 5) 6) 7) • (CDR '((3 (4 5) 6) 7)) = (7) • (CDR '(7)) = () • Answer: () or nil PARENTHESIS ARE REQUIRED!!!