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 Designed by David G. Kay

 This KLA is transcribed from the SIGCSE 2004 Special Session on KLAs.

Overview To KLA

 Learning Goals: At the end of this exercise, students will understand...

 • Algorithms (general idea)
 • linear vs. log time
 • parallelism
 • divide and conquer
 • experimental analysis of running time

 Course And Level: As young as kindergarten (5 years)

 Class Size: minimum of 30 or so for good results

 Preparation Time: none

Planning For KLA
 Materials:
 • A stack of index cards (or punch cards)

 Preparation:
 Introduction to group: Computer scientists study algorithms. An algorithm is a process, a procedure, like following a recipe. We can study which way of doing something, which algorithm, takes less time. We can do an experiment.
 Here is a pile of cards. We want to pass them around so each person has one. We have two algorithms, "Pass the pile" and "Split the pile".

 As always, read this description carefully and practice the KLA before using it in class!

Execution Of KLA

 Description:
 Explain "Pass the pile" and do a short dry run: Each person takes a card, gives the pile to the next person, then goes and stands by the wall. *

 Explain "Split the pile" and do a short dry run: Take card, divide remaining pile in two (not necessarily perfectly equally), give each pile to someone else, and then go stand by the wall. *

 Have someone be the timekeeper and count out seconds(or keep track silently).
 1 Start off with "Pass the pile". Give pile to one person. Start the timekeeper, stop when everyone has a card.
 2 Reassemble the group. Re-collect the cards. Start off with "Split thew pile" (perhaps with a reminder of how it goes). Have timekeeper count. Stop when everyone has a card.
 3 Compare times. Hope "Split the pile" was shorter. Ask class why. Discuss.

 *I did this with a group of about 40 5 and 6 year olds. To keep them from milling around and interfering with the process after they got their cards, I had them go stand aside once they had a card.

Variants And Extra Topics:

Constraints On KLA

 • Limited Vision:
 • Limited Hearing: Only issue is delivering instructions. You could write them out.
 • Limited Mobility:
 • Trouble Speaking:
 • Touch Aversion:
 • Other:

Pitfalls Of KLA

 Once you have a card, have young people do something like go to the wall - their seat!

Feedback And Use Notes