Shayan's blog

Codeforces Educational Round 168 (Div. 2) — Video Tutorial
By Shayan, history, 6 weeks ago, In English

1997A — Strong Password

1997B — Make Three Regions

1997C — Even Positions

1997D — Maximize the Root

1997D — Maximize the Root — O(n) Solution

1997E — Level Up

1997F — Chips on a Line

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6 weeks ago, # |
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Is it just me or did almost everybody get fail testcase 19 on D at least once? Took me 30 mins to find the overflow.

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    6 weeks ago, # ^ |
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    I am getting error in test case 19 too. what was the issue with yours?

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      6 weeks ago, # ^ |
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      he mentioned overflow

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        6 weeks ago, # ^ |
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        Like what specifically was overflowing

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          6 weeks ago, # ^ |
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          It took me a long time to fix this problem

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          6 weeks ago, # ^ |
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          Make a line graph with value of root node as 1 and for all other node as zero. You will see that the 'value needed' will essentially double each time and so if you have more than 32 or 64 nodes(depends on whether you took integer or long long), it will overflow

          1<--0<--0<--0.....

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6 weeks ago, # |
← Rev. 3   Vote: I like it 0 Vote: I do not like it

a

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6 weeks ago, # |
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A,B I read for more than three time.

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6 weeks ago, # |
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can you add some subtitles to the video? I would appreciate it because it is really hard to understand for us foreigners

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    6 weeks ago, # ^ |
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    YouTube automatically adds after 1k views

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6 weeks ago, # |
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How irritating questions like B are . Very confusing needs to read three to four time to understand what actually the question wants.

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6 weeks ago, # |
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nice F:)

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6 weeks ago, # |
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I just purely want to know how to reach 1500 rating ? Concretely , Div 2 need to this level , which solved three problem in time ? Could anyone instruct me , please?

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    6 weeks ago, # ^ |
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    You want to reach 1500, yet 75% of your solved problems are rated below 1500. Just practice problems +200 of your rating.

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      6 weeks ago, # ^ |
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      "I mean, what kind of performance is needed in Div2 or Div3 to reach a rating of 1500?"

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        6 weeks ago, # ^ |
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        In Div. 2 it is enough to solve ABC, doesn't matter how fast, in Div. 3 solve ABCD fast or ABCDE. Take this with a grain of salt since contest difficulty varies. I would recommend downloading the Carrot extension which allows you to see your performance in the standings page.

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          6 weeks ago, # ^ |
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          Thank you for your recommendation , I will effort to raise my rating and wishing you get better rating on next Round than ever!

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