Diagram

[giladedelman]

Here's another solution to the second game in PT 55. Let me know if you have any questions!

[Pld70]

I do not see how the HJ chunk is required. I see nothing in the rules to mandate the chunk. Rule #3 does say J day after H but that could be HLJ in either 1,2,3 or 4,5,6 and not violate any rules. question # 11 throws me for a loop and wasted a lot of time. Why could it not be JHLHLJ whch makes the "D" answer incorrect? Please explain, anyone.

[ohthatpatrick]

The chunk, as you implied, comes from rule 3. If they say that Jerome leaves a message the day after Hilary does, then that is HJ, not H - J.

Your counterexample of HLJ would break rule 3. If H is day 1 and J is day 3, does Sukanya receive a message from Jerome on the day after receiving one from Hilary?

No, with HLJ, she receives a message from Lula on the day after receiving one from Hilary.

I think you're interpreting Rule 3 as "receives a message sometime after receiving one from Hilary".

Let me know if you still have concerns about that rule.

In terms of Q11, you should check out the explanation for Q11 on the forum and add your question there if you still have one:
q11-t7379.html

But the quick answer to "Why not JHLHLJ" is the same as the above: that scenario breaks rule 3. Nowhere in that scenario does J come the day after H.

Hope this helps.

[seychelles1718]

So would the meaning of the rule #3 not be affected even if there were no "exactly once" placed at the beginning of the sentence?

Also, I misinterpreted this rule under timed test and thus thought it meant that we can't have any J after the HJ block; in other words, I though the rule was saying "HJ - J is impossible".

The wording and grammar of this rule really threw me off. Any suggestions on how to interpret the rule clearly?

[ohthatpatrick]

The meaning would change if it didn't say "exactly once".
We would then be able to do HJ twice.

The part of the rule/grammar that is exact spacing rather than relative ordering is that it says "THE day after Hillary", not "SOME day after Hillary".

You could potentially help your brain interpret it correctly by setting the "Exactly once" to the side for a sec, in order to focus on what thing they're saying happens exactly once.

This happens exactly once:
S receives a message from J on the day after receiving one from Hillary.

So first let's figure out how we're going to represent that idea: "a message from J on the day after receiving one from Hillary" ... okay, so "HJ".

Now we can say
EXACTLY ONCE, we'll see "HJ".

This doesn't tell us anything about other H's or J's we'll see, other than ruling out the possibility of a second "HJ".

[NatalieC941]

At first I had difficulty picturing this game because I couldn't tell if a "day" could be left open (ie. does there have to be a message sent every day?). Based on the wording it just says Sunkaya "receives at least one and no more than two from each of them." It also says, "No more than one message is sent each day." To me, none of this implied that there could be a left open/off/no-message day.

Am I missing something?

It wasn't until I looked at #7, that I decided the author probably hadn't intended any off-days.

___
EDIT... Maybe I just realized my own answer because the number of days technically don't matter but instead the number (and ordering) of messages. Is that right?

[ohthatpatrick]

That's exactly right ... and I had the exact same "moment" with a class the other night.

We were all looking at the language of the setup, expecting to see some "one message per day" boilerplate stuff and were surprised we couldn't find it. Then we ultimately concluded what you did: the order of things is never day-specific, it's just sequence-specific.

You can be the 3rd message whether or not you landed on the 3rd day.

[AndrewB184]

What does the 1J* refer to in the diagram?