aquamongoose's blog

Google Code Jam 2013 Qualification Round
By aquamongoose, 12 years ago, In English

It starts in just over an hour, and will last 25 hours.

Link for registering/competing here.

Good Luck!

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12 years ago, # |
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Am I right that X points after systests is enough to advance?
X = 100?

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    12 years ago, # ^ |
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    Qualification Round 2013 — Contestants with 35 points advance to the next round.

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    12 years ago, # ^ |
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    I also searched for this information for some minutes: It's in the head line of the scoreboard.

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12 years ago, # |
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y for larger input data,the results will be announced after the contests?? <>

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12 years ago, # |
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How to solve D-Large?

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    12 years ago, # ^ |
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    One can prove that you can open all the chests iff you have enough keys of each color (including keys in closed chests) and for each unopened chest you can open by some openings sequence (can be checked by dfs). Now you can open chests one by one greedily preserving this property.

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12 years ago, # |
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What is the solution to C , 2nd large ?

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    12 years ago, # ^ |
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    First reference sequence and Second reference sequence

    Backtrack to generate all the palindromes (most of the cases will be pruned quite early, and in total there are only 41551 palindromes whose value is less than 10^100).

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      12 years ago, # ^ |
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      What do you mean by backtrack in this case? Is there a property that allows you to generate square palindroms of length n given all square palindroms of length < n?

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        12 years ago, # ^ |
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        You can notice the title of the sequence here: "Palindromes whose square is a palindrome; also palindromes whose sum of squares of digits is less than 10". And then you can generate all palindromes by iterating over the first half of the number (25 digits maximum), add a reversed second half, square it and get one asked number.

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          12 years ago, # ^ |
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          Also, if A[i]>=B[i], where A is first half of the number, which square is palindrome too, then B's square is also a palindrome. Palindrom generation works almost instantly.

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12 years ago, # |
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Does anyone know how to get stats data (such as how many coders solve a problem, etc) from GCJ scoreboard? I just want to do some data analysis with GCJ data.

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