1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Greedy Algorithm

  1. Oct 3, 2011 #1
    1. The problem statement, all variables and given/known data
    See photo 1 for question
    photo 2 for tutorial

    2. Relevant equations

    3. The attempt at a solution
    I have 2 questions

    1. It seems the 2 methods in part(a) are not optimal.
    But I don't know if my counter examples are correct.
    If we use the (1) algorithm, that in my drawing 1, it choose event A only. However, choosing B, C and D is better.
    If we use (2), that my second drawing shows it will choose either C or B. However, choosing A and D is better.

    2. In part b, how to calculate the time needed?
    For me, I decompose the greedy algorithm in to 4 steps.(See the tutorial sheet to see which 4 steps)

    I know that step 1 takes n times because it compare n events.
    step 2 doesn't take time because it choose the event only.
    step 3 takes n times again since it compares n events to see which one has time crash and then discard them.

    I think step 4 is the tricky. It repeat step 3 with fewer events. I assume i events have been discarded, but I am sure if I can do this.

    Attached Files:

  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted