CS 561: Fall 2004, Homework Assignment #1

Due Thursday, September 9, 2004


Problem 1. Solve the following recurrences by unrolling the recurrence (or listing the first few values), guessing the solution, and proving it correct.
  • f(n) = 3f(n-1) + 1, f(0) = 0
  • f(n) = 2f(n/4) + 1, f(0) = 0

  • Problem 2. Solve the following recurrences in asymptotic terms (initial conditions are not given, as they do not influence asymptotic behavior for algorithms). Show your work.

  • f(n) = 5f(n-1) - 6f(n-2)
  • f(n) = 2f(n-1) - f(n-2)
  • f(n) = 3f(n-1) - 3f(n-2) + f(n-3)

  • Problem 3. Show how to transform the following recurrences into finite-order recurrences and solve them in asymptotic terms.

  • f(n) = 3f(n/3) + n2
  • f(n) = 2f(n/2) - f(n/4) + (logn)2
  • These recurrences have both a homogeneous and a inhomogeneous part, so solve them separately, then decide which dominates the behavior.