A problem for you ...
Three missionaries and three cannibals stand on the bank of a river that they wish to cross. There is a boat available which can ferry up to two people across. The goal is to find a schedule for ferrying all the cannibals and all the missionaries safely across the river. The constraint is that, if at any point the cannibals outnumber the missionaries on either bank, the cannibals will eat the missionaries. Note that the boat cannot cross the river by itself with no people on board.
Sounds like my weekend! Substitute children for 'cannibals,' parents for 'missionaries,' car for 'boat' and across town for 'river' and you have my dilemma. Actually, it would be better to have this problem as we know there is
an answer. That wasn't the case for the problems we faced.
There are lots of annoying things about kids' parties. One of the biggest is that they get invited to them. What is more, the potential number of parties one child might get invited to in a year is related to but not limited by the number of children that happen to be in their class. Indeed, my belief is that the biggest cost of increasing class sizes is the lost weekend time due to all the extra parties.
So this weekend a, fortunately rare, event occurred. Two of our children had two parties each on the same day at the same times. Child No.1 had a party at 10:30am (seeing
Shrek again) that was due to end at 1:45pm and she had another party (this time bowling) due to begin at 1:15pm and end at 3 or so. Child No.2 had a party beginning at 10:30am and ending at 12:30pm (at a park) and then another from 1pm until 3pm (video gaming or something). Child No.3 had no party but really needed a nap from 1-3pm.
Think you can solve this: well, I am not done yet. This would all be well and good if we were at the same place for all this. But of course not. Without going into the details, Child No.2's first party was at location A which was 20km from Child No.1's first party at location B. Child No.2 then had a party at location B while Child No.1's second party was at Location B (sort of) in terms of parking but actually half a kilometer a way by foot.
But even that is complicated so to plan at least the location side of things out I did a mash-up in Google Maps (
here is the link in case you are interested). Suffice it to say, there were real issues here. Our children's mother suggested the problem was "
np-incomplete." I said, "you think!"
Nonetheless, there needed to be a plan and so one came. Clearly, I could not deposit both children at their desired Party 1's at 10:30am as they were 20km apart. We could use the other adult but instead tried to broker a deal with another parent who had a child going to both Child No.2's birthdays. The plan was this: I would take both children with me and head out from home at 9:45am. We would deposit Child No.2 at friend's house at 10am (also approximately marked on the map). Sadly, this was close to his party and 20km or so from Child No.1's first party. I would then drive Child No.1 to her first party and return home. So far so good.
Now you might think that next part of the plan would involve the other parent ferrying Child No.2 and friend to the next party. Sadly no. As I was going to have to be at the location for that party in order to transfer Child No.1 between parties there, it seemed better if I did that transfer.
So you might ask: why not find a parent to transfer Child No.1 between her two parties? That would have freed up the middle of the day. Well, it turned out that there was no overlap between the kids in Child No.1's two parties even though they were in the same class! Why? Because the first party was a girl's party and the second party was not. Now again, you might be puzzled as to how we became the only point of intersection. Well, you see Child No.1, while physically a girl, is, in fact, a boy. So she gets invited to both parties. The upshot of all this ridiculousness, is that I had to be on site for the transfer.
But then we had another intractable issue because Child No.1's first party ended half an hour after her second party began. Something had to by thrown out and it turned out to be Child No.1's lunch. I would deposit Child No.2 and friend at Party 2 at 1pm and then collect Child No.1 at 1:05pm and somehow get to her next party by 1:15pm. It was a bowling party so we couldn't really be late.
From then on, the plan would be that I would collect Child No.1 at 3pm while the other parent collects Child No.2 and friend at the same time and brings them back to our house. All the while, their mother stays with Child No.3 who gets her nap and so the day is solved.
I announced the plan. Then their mother piped up, "I was hoping to get a swim in today." Following that, one parent was wiped from existence.
OK but this post isn't done yet. How did the plan go? It all looks nice and clean on Google Maps but there are obstacles. First, there is the issue of presents. You see, not only do children have to be transported to various parties but their presents do too. What you don't want to do is have a child responsible for transferring a present between parties as it is likely to get lost. Again, the missionary/cannibal issue comes up but with a third set of things to be transported. So I needed to make contingency plans for the presents. This involved loading up the car with all said presents and also, and I was particularly proud of myself for anticipating this one, friend of Child No.2 needs to have his present loaded into my car right at the beginning so that I had both their presents during the crucial party 1 to 2 transfer at 12:30pm. What this did mean is that I transported that present around all day. The present failed to note the irony of that one during the part of the journey we were alone together.
Second, sometimes it is not clear what you are supposed to do with regards to parties. When I arrived at Child No.2's first party to pick him up, I found it was a gigantic park. Where were they supposed to be? I phoned home and the invitation at Packer Park (or Oval Reserve) said they were in the Packer Pavilion. It wasn't obvious where that was. On the phone I requested support. I was expecting a high level of support given my logistic circumstances; you know, like Jack Bauer would get in
24.
"Call up a schematic of the park and transfer it to my PDA."
"You don't have a PDA."
"Well, my Blackberry then."
"I am not sure I can do that."
"You know I have no room for error here."
"OK, look for a big blue building at the South end of the park, latitude 145.3188 degrees South, longitude 37.540614 degrees East.
"Got it. Thanks. Was that so hard?"
Anyhow, I went inside and found all of the children in their pyjamas; apparently, some person's bright idea of a theme! Well, except one, Child No.2. That was fine: it was winter and he had another party to go to. His friend was dressed like that and we negotiated another five minutes was to whether he had a change of clothes for his second party. Apparently not. But we were now late.
Third, there is traffic. Now you might think that on a Sunday traffic isn't a problem. Not so. Three parties were located in a traffic and a parking disaster. So to get the last mile to that location takes at least 20 minutes. During that time traffic moves at a crawl as people try to find parking. I had finally spied a parking space on my first run into that area when someone in front of me scooted into it. I immediately took my thumb and forefinger out to apply The Force choking trick to them.
Child No.1 commented, "Dad, you know that doesn't work outside of Star Wars."
I replied, "It works for me."
"Do they really deserve to die? They were there first."
"You know, I am not planning to kill them. Darth Vader just made them uncomfortable. Just let me have my fun."
Which brings me to the final obstacle, parking. On run one, I found a space pretty easily. Run two was a nightmare, traffic and parking wise. We arrived 10 minutes late for Child No.2's second party and then, because I didn't want to give up my spot, I gathered Child No.1 and raced to her second party; arriving late for that. During which time I was informed that there had been a change of plans and Child No.1 would now be collected by someone else, taken to their house and we would pick her up later. I took the long walk back to the car and got some lunch.
And here I am writing this post while Child No.3 has her nap and her mother, who it turns out did survive the planning stage, goes for a swim. I have done 50kms driving, a 1km run and have spent 3 hours in the car and I am not done yet as neither child has actually been brought safely home. Not that a failure to do so would be totally bad (at least with regards to future parties) but the cannibals are supposed to get to the other side of the river in the correct solution to the problem.
So to the moral of this story: "no child gets more than one party in a day" is a good rule. Let them choose who their friends really are. Otherwise not all the missionaries are going to make it to the other side.