xiaowuc1's blog

By xiaowuc1, 6 weeks ago, In English,

Hi all,

The third contest of the 2019-2020 USACO season will be running from February 21st to February 24th. Good luck to everyone! Please wait until the contest is over for everyone before discussing problems here.

 
 
 
 
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6 weeks ago, # |
  Vote: I like it +31 Vote: I do not like it

Excited for USACO as always! Wish everyone good luck :)

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6 weeks ago, # |
Rev. 2   Vote: I like it +8 Vote: I do not like it

Do you have an exact time when we can discuss this contest?

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    6 weeks ago, # ^ |
      Vote: I like it +16 Vote: I do not like it

    4pm UTC (11am EST) on Tuesday, if I calculated correctly.

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6 weeks ago, # |
  Vote: I like it +21 Vote: I do not like it

Has the contest finiished so that we can discuss the problems?

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6 weeks ago, # |
  Vote: I like it +1 Vote: I do not like it

How to solve all problems in platinum?

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6 weeks ago, # |
Rev. 2   Vote: I like it +41 Vote: I do not like it

Notes:

What's the answer for N=1 in DELEG (Plat)?

O(knlogn) requires a bit of optimization to pass for HELP (Plat)?

Plat sols:

DELEG
TRIANGLES
HELP

Trash 2:28 AK Screencast

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    6 weeks ago, # ^ |
      Vote: I like it +23 Vote: I do not like it

    'Trash'

    The video is private I think

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      6 weeks ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      I think that a lot of people AKed much faster than I did, for example you can look at 300iq's screencast where he AKs in 1:23

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    6 weeks ago, # ^ |
      Vote: I like it +16 Vote: I do not like it

    "What's the answer for N=1 in DELEG (Plat)?"

    Clearly it should be INT_MAX :D

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    5 weeks ago, # ^ |
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    For DELEG: For the root, you can simply ignore the circumstance of dp[root] = 0 if you pick a leave as root.

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5 weeks ago, # |
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How to solve problem HELP(gold)?

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    5 weeks ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    Answer = ∑ ( 2^(n-1-the number of the segments which cover l[i] ) )

    Use segment tree you can pass in O(nlogn).

    But I don't how to solve HELP in Plat with this Idea.

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    5 weeks ago, # ^ |
    Rev. 2   Vote: I like it 0 Vote: I do not like it

    Use expected values and then sweepline to pass all test cases, so no need to do segment tree.

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5 weeks ago, # |
Rev. 2   Vote: I like it -10 Vote: I do not like it

I think problem P1 is particularly similar to China's NOIP2018 D1T3.

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5 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

Will 710.4 be enough to pass gold?

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    5 weeks ago, # ^ |
      Vote: I like it +9 Vote: I do not like it

    Im guessing cutoff is not going to be like 750+, since 2 of the problems were kind of hard. But honestly, it seems like contestants are getting smarter nowadays so it is quite difficult to predict.

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      5 weeks ago, # ^ |
        Vote: I like it +5 Vote: I do not like it

      I think this month's cutoff was similar to last month's difficulty so I'm crossing my fingers that cutoff will be the same.

      By the way, how many days does it usually take for the results to come out?

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5 weeks ago, # |
  Vote: I like it +58 Vote: I do not like it

When will USACO be releasing results?