Generic Solution

Conceptual Pattern

Mark the guests to be counted one-by-one and count them while performing the marking function. (cf. StarTrek episode xxx)

Design Pattern

The design pattern describe the relations among the parts of a solution.

        -----------------
     ---| Mark and Count|---
     |  -----------------  |
     |                     |
----------             ----------
| Marker |             | Guests |
|        |<----------->|        |
----------             ----------


OR MORE CONCISELY

------------------
| Mark and Count |
------------------
       |
       |
    --------
    |Guests|
    --------

Programming Pattern

If the solution is a software solution, then we can have a programming pattern. Otherwise we can stop at the design pattern.

Solution 1

Brandon A. Spires

Conceptual Pattern

Problem: Reliably count how many people are present in a crowded room.

Context: very noisy environment, where everyone is drinking, laughing and shouting because the Steelers just won the superbowl.

Constraint: must count the people before they leave to go home (.5 to 1 hour timeframe)

Forces:
1. People enter and leave the room at will
2. People may leave the party late or at different times

Solution:
a. The hosts wear red tags, numbered in the order that they leave the room. The number one goes to the first person to leave the room, etc
b. A host gives red tags to each guest as they leave the room, whether they leave for a bathroom break, more food, or to go home. The tags are numbered in increasing order
c. If a person re-enters the room, then they do not receive another tag
d. The last number given out represents all of the guests that were in the room at the end of the superbowl.

Reuses:

This solution can be used in any situation where there are people or livestock in a room that must be counted. For example, if one needs to count how many cows they have, all they need to do is to follow these steps.

Design Pattern

Solution 2

Samantha Kuhn

Solution: Since people are celebrating and moving around, it not reliable to try and count the number of people by hand. Instead, since everyone is drinking, take the number of used cups as the count for the number of people at the party

Conceptual pattern

1) First, count the number of glasses before the party, or ask the host.
2) Once everyone has arrived and gotten their cup, count how many are left during the celebration.
3) Take the number before the party (1) and subtract the number left (2) to get the number of people at the party.

Example: If the party host bought a bag of 200 plastic cups, and only 50 are left, it is safe to say there are approximately 150 people at the party.

People may argue that not every guest will grab a cup. People will also argue that some guests will throw away/discard their cup and grab another. Both of these possibilities will cancel each other out. Example: Sally doesn.t want a drink, so she doesn.t get a cup. Bob takes one cup and accidently destroys it, so he gets another. Sally + Bob = 2 people. Sally.s cup (0) + Bob.s cup (2) = 0 + 2 = 2 cups = 2 people. It evens out. Not every pattern can be perfect, but this will be mostly reliable.

Design pattern catalog

Counting People in a Room
Host	Calculator
Bought Cups	Get Total Cups	Count Cups Left	Subtract Cups

**Note: Calculator could be you (mental math)

c) Solution applied to another problem.

This solution pattern can be applied to any store, such as Home Depot, to count the number of sold items. You know the number of lawnmowers you started with, say 10. At the end of a week, only 3 are left. By using the pattern, subtract 3 from 10 and you are left with 7. Seven lawnmowers were bought in the week. This pattern allows one to not have to watch and count each lawnmower bought, but just do some basic subtraction to figure out the number of lawnmowers sold.