9. References & More Lists

  • Feel free to use your laptop

  • You are strongly encourage to work with others

    • When you get stuck, ask those sitting around you for help

    • Get used to working together in the labs

    • Peer teaching and peer learning has been empirically shown to be very effective

9.1. Pre Lab Exercises

  • For all exercises

    • Use assert to test instead of their test function

  1. Chapter 14 exercise(s)

    • 2 — Note the portions of solutions within the chapter text

    • 3

    • 4

    • 5

  2. Write assertion tests for each of your functions above

9.2. Before Kattis

  1. Run the following code and figure out what it does and how it does it

    • I want to see everyone with paper here working through the logic

    • If you can’t figure it out, hack around with the code

      • Comment out bits

      • Print out values

      • Do whatever you need to do to figure it out

    1a = [0, 0, 0]
2b = [a,a,a]
3
4for row in b:
5    to_print = ''
6    for d in row:
7        to_print += str(d) + ' '
8
9    print(to_print)

  2. Add b[1][1] = 1 to line 3 and run it again and see what happens

    • Is this what you expected?

  3. Alter the code such that the output will be what’s below

    • Change the list setup/creation part, not the loops

    0 0 0
0 1 0
0 0 0

  4. Add b[0][1] = 1 to line 3 and run it again and see what happens

    • Is this what you expected?

  5. Given a list of integers, return, in a list, indices of two numbers such that they add up to a specific target

    • You may assume that each input would have exactly one solution

    • You may not use the same element twice

    • For example, given nums = [2, 7, 11, 15], target = 9

      • Since nums[0] + nums[1] = 2 + 7 = 9

      • Return [0, 1]

  6. Think about how much work your algorithm for the previous question had to do in terms of \(n\), where \(n\) is the length of the list

    • Can you somehow think of a better algorithm that would do less work?

    • Don’t spend too much time on this if you can’t come up with a solution

    • Hint: Dictionaries (but leave the nums list alone)

9.3. Kattis Problems

  • You should be using a scrap piece of paper to work out the ideas for the following problems

    • The problems you are to solve are getting too complex to try to solve by just coding

    • Trying to solve problems by just typing away will not yield success

  1. https://open.kattis.com/problems/bijele

  2. https://open.kattis.com/problems/cold

  3. https://open.kattis.com/problems/nastyhacks

  4. https://open.kattis.com/problems/grassseed

  5. https://open.kattis.com/problems/pet

  6. https://open.kattis.com/problems/batterup

  7. https://open.kattis.com/problems/aboveaverage

  8. https://open.kattis.com/problems/icpcawards

  9. https://open.kattis.com/problems/quickbrownfox

  10. https://open.kattis.com/problems/nodup

  11. https://open.kattis.com/problems/conundrum

  12. https://open.kattis.com/problems/bela

  13. https://open.kattis.com/problems/kornislav