Life In 19x19

• Round 1 (April 28 2017)

• Round 2 (May 6 2017)

• Minimum Spanning Tree (MST)
• Single source shortest path (SSSP), non-negative weights
• SSSP, time table
• SSSP, negative weights
• All pairs shortest path
• Eulerian path
• Max Flow
• Min-cost Max Flow

quantumf wrote:Dominoes 2 is the first really ambiguous question I've seen. Can someone who's solved it explain:

Does a domino knocked over by hand count as "fallen"?
Does the starting domino count as "fallen"?
Can we assume that something magical starts the process?

Or, put in terms of the only given test, is the answer 2 because 1 falls over, then 2 doesn't fall over, then 2 is manually knocked over, after which 3 falls, so its 2 because of 1 and 3, or is 2 because the starting domino is 2, knocked over by hand, which knocks over 3, so the answer is 2 because of 2 and 3?

Schachus wrote:Hey, I tried to do something, but I'm already not sure how to read the input.

can someone tell me if this code in java would achieve reading the input(of the first problem) into a matrix called "karte"(and if not, what do I need to do to achieve that?)

bernds wrote:

Schachus wrote:Hey, I tried to do something, but I'm already not sure how to read the input.

can someone tell me if this code in java would achieve reading the input(of the first problem) into a matrix called "karte"(and if not, what do I need to do to achieve that?)

Not about to comment on Java code since I'm not competent. Easiest way to find out is to print out the map from what you read in and see if it matches what you expect.

Schachus wrote:

bernds wrote:

Schachus wrote:Hey, I tried to do something, but I'm already not sure how to read the input.

can someone tell me if this code in java would achieve reading the input(of the first problem) into a matrix called "karte"(and if not, what do I need to do to achieve that?)

Not about to comment on Java code since I'm not competent. Easiest way to find out is to print out the map from what you read in and see if it matches what you expect.

Thanks,
That is what I tried and it didnt work, but I wasnt sure whether is was cause the code doesnt work, or because I somehow messed up the console message specifying input and output...

bernds wrote:

quantumf wrote:Dominoes 2 is the first really ambiguous question I've seen. Can someone who's solved it explain:

Does a domino knocked over by hand count as "fallen"?
Does the starting domino count as "fallen"?
Can we assume that something magical starts the process?

Or, put in terms of the only given test, is the answer 2 because 1 falls over, then 2 doesn't fall over, then 2 is manually knocked over, after which 3 falls, so its 2 because of 1 and 3, or is 2 because the starting domino is 2, knocked over by hand, which knocks over 3, so the answer is 2 because of 2 and 3?

It's easier if you just ignore the sentences "However, sometimes a domino fails to knock the next one down. In that case, we have to knock it down by hand to get the dominoes falling again."

And yes, knocked down by hand means fallen - you can tell from the example. It's a simple problem.

quantumf wrote:Thanks, that helps. The sparse test data and vague phrasing means it's ambiguous and anything but simple. Follow up question - what is the point of the m pairs? Surely there will be a pair for every domino (1:2, 2:3, 3:4 etc up to n-1:n)? Or should we deal with potential gaps, or pairings that are not consecutive, e.g. domino 2 knocks over domino 7, or even worse, domino 6 knocks over domino 3?

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bernds wrote:The numbers are just there to unambiguously identify each domino, they do not specify how they are placed on the table. You could place dominos like this (view from above, these are supposed to be three dominos in a triangular formation), and pushing the right one over to the left would topple the other two.

Code: Select all

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The other way to go about it is to consider the theme of this round and think about how it relates to this problem.