[Script Info] Title: [Events] Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,As a wildfire rages through\Nthe grasslands, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,three lions and three wildebeests\Nflee for their lives. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,To escape the inferno, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the must cross over to the left bank\Nof a crocodile-infested river. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Fortunately, there happens\Nto be a raft nearby. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,It can carry up to two animals at a time, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and needs as least one lion\Nor wildebeest on board Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,to row it across the river. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,There's just one problem. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,If the lions every outnumber the\Nwildebeest on either side of the river, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,even for a moment, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,their instincts will kick in,\Nand the results won't be pretty. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,That includes the animals in the boat\Nwhen its on a given side of the river. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,What's the fast way for all six animals\Nto get across Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,without the lions stopping for dinner? Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Pause here if you want \Nto figure it out for yourself. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Answer in: 3 Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Answer in: 2 Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Answer in: 1 Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,If you feel stuck on a problem like this, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,try listing all the decisions you can make\Nat each point, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and the consequences each choice\Nleads to. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,For instance, there are five options\Nfor who goes across first: Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,one wildebeest Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,one lion. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,two wildebeest, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,two lions, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,or one of each. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,If one animal goes alone, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,it will just have to come straight back. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,And if two wildebeest cross first, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the remaining one will immediately\Nget eaten. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,So those options are all out. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Sending two lions, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,or one of each animal, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,can actually both lead to solutions\Nin the same number of moves. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,For the sake of time,\Nwe'll focus on the second one. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,One of each animal crosses. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Now, if the wildebeest stays \Nand the lion returns, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,there will be three lions\Non the right bank. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Bad news for the two remaining wildebeest. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,So we need to have the lion\Nstay on the left bank Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and the wildebeest go back to the right. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Now we have the same five options, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,but with one lion \Nalready on the left bank. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,If two wildebeest go,\Nthe one that stays will get eaten, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and if one of each animal goes, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the wildebeest on the raft\Nwill be outnumbered Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,as soon as it reached the otherside. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,So that's a dead end, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,which means that at the third crossing, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,only the two lions can go. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,One gets dropped off, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,leaving two lions on the left bank. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,The third lion takes the raft back to\Nthe right bank Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,where the wildebeest are waiting. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,What now? Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Well, since we've got two lions waiting\Non the left bank, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the only option is for two wildebeest\Nto cross. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Next, there's no sense in two wildebeest\Ngoing back, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,since that just reverses the last step. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,And if two lions go back, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,they'll outnumber the wildebeest\Non the right bank. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,So one lion and one wildebeest\Ntake the raft back Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,leaving us with one of each animal\Non the left bank Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and two of each on the right. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Again, there's no point in sending \Nthe lion-wildebeest pair back, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,so the next trip should be either\Na pair of lions Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,or a pair of wildebeest. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,If the lions go, they'd eat the wildebeest\Non the left, so they stay, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and the two wildebeest cross instead. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Now we're quite close because the\Nwildebeest are all where they need to be Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,with safety in numbers. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,All that's left is for that one lion\Nto raft back Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and bring his fellow lions over\None by one. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,That makes eleven trips total, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the smallest number needed\Nto get everyone across safely. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,The solution that involves sending both\Nlions on the first step works similarly, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and also takes eleven crossings. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,The six animals escape unharmed\Nfrom the fire just in time Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and begin their new lives \Nacross the river. Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Of course, now that the danger's passed, Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,it remains to be see how long their\Nunlikely alliance will last.