Shayan's blog

Codeforces Round 960 (Div. 2) — Video Tutorial
By Shayan, history, 4 months ago, In English

1990A — Submission Bait

1990B — Array Craft

1990C — Mad MAD Sum

1990D — Grid Puzzle

1990E2 — Catch the Mole(Hard Version)

Not a formal proof! (please explain the formal proof of the algorithm in the comment section if you know that)

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4 months ago, # |
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Congrats for reaching 10K dude <3

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4 months ago, # |
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Why video editorial?

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    4 months ago, # ^ |
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    text editorials take time to complete , besides Shayan does some clean coding too , so its nice in the mean time.

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    4 months ago, # ^ |
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    The authors will prepare the text editorial.

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4 months ago, # |
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Can someone please explain problem D? I understood everything in the editorial up until adding the second dimension to the dp array. I don't get that part, why do we add dp[i][j] where j can be {0,1,2,3}? And is there a way to solve this without adding this second dimension?

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4 months ago, # |
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Problem D can be solved using greedy: https://codeforces.net/contest/1990/submission/271628945

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4 months ago, # |
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The "A.Submission Bait" problem really lives up to its name

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4 months ago, # |
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Problem D greedy solution with just 2 variables and one for loop: 271663296

Idea/Solution
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    4 months ago, # ^ |
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    Same idea here, but tracking column indices instead: 271665697

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    4 months ago, # ^ |
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    trash ass solution. clearly codeforces is not for u lil bluh

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      4 months ago, # ^ |
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      What didn't you like about it? Maybe we can improve if u tell us so.

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4 months ago, # |
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Please add Russian subtitles to the video

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4 months ago, # |
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Shayan, could you please answer this.... for Problem D, dp[i][j], j={0,1,2,3} what is the j here ? , is it {00,01,10,11} where each boolean value tell us about the use of the 1st and 2nd 2x2 block in i_th row ?

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    4 months ago, # ^ |
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    Exactly. It shows the 4 possible ways for the 1st and the 2nd 2*2 block in the row number i.

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4 months ago, # |
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why is it getting downvoted?

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