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Panasonic Programming Contest 2025（AtCoder Beginner Contest 406） Announcement
By atcoder_official, history, 17 months ago, In English

We will hold Panasonic Programming Contest 2025（AtCoder Beginner Contest 406）.

We are looking forward to your participation!

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17 months ago, hide # |
 
Vote: I like it +11 Vote: I do not like it

website not loading. 500 Internal Server Error

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17 months ago, hide # |
 
Vote: I like it +3 Vote: I do not like it

Why is there a 500 Internal Server Error?

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17 months ago, hide # |
← Rev. 2  
Vote: I like it -8 Vote: I do not like it

Problem D is repeated. If I'm not mistaken then I solved the same problem with a different statement or a problem with the same logic in a recent ABC.

The problem

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17 months ago, hide # |
 
Vote: I like it +16 Vote: I do not like it

I thought a persistent version of F could be an interesting problem.

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17 months ago, hide # |
 
Vote: I like it +15 Vote: I do not like it

In my opinion: G>C>E>D>F>B>A

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17 months ago, hide # |
 
Vote: I like it +16 Vote: I do not like it

promble C should not be promble C

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17 months ago, hide # |
 
Vote: I like it 0 Vote: I do not like it

I found Problem F to be quite similar to Problem D of Recent LeetCode Biweekly Contest 154.

Similar logic can be applied though; I ran out of time to solve it..

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17 months ago, hide # |
 
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The quality of problem E is very high. Problem F is too formulaic and can be solved with a simple tree decomposition, or even without it, just using DFS order + Fenwick tree.

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    17 months ago, hide # ^ |
     
    Vote: I like it 0 Vote: I do not like it

    I think I'm the only one who is so dumb as to use tree decomposition to solve F

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17 months ago, hide # |
 
Vote: I like it +1 Vote: I do not like it

F is much easier than E for me.

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17 months ago, hide # |
 
Vote: I like it +2 Vote: I do not like it

It took me a long time to solve problem E, so I didn't have time to solve problem F

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17 months ago, hide # |
 
Vote: I like it 0 Vote: I do not like it

I got 6 WA on B idk where I went wrong

can someone tell me their approach?

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    17 months ago, hide # ^ |
     
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    did you check for overflow ?

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      17 months ago, hide # ^ |
       
      Vote: I like it +3 Vote: I do not like it

      i checked for overflow as well but the editorial also said that the overflow would be so quiet often that you cant always have a track of it.

      They used a really clever technique to see whether the multiplication exceeds k digits

      Anyway appreciated for the reply

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17 months ago, hide # |
 
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For E , I used bit dp to get count & sum of numbers and I am getting WA . Can someone provide me relevant test case where my Code fails.

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    17 months ago, hide # ^ |
     
    Vote: I like it 0 Vote: I do not like it

    exact same failure pattern for me too.. using digit dp ... :(

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      17 months ago, hide # ^ |
       
      Vote: I like it 0 Vote: I do not like it

      can you explain the code for digit dp?

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        17 months ago, hide # ^ |
         
        Vote: I like it 0 Vote: I do not like it

        I am not very good at digit dp .. so didn't do it during contest but I can give high level idea and also I can't explain it very well .. here is my submission

        https://atcoder.jp/contests/abc406/submissions/65933199

        first I counted how many numbers with K bits are possible which happens in recurCnt .. the idea is to keep track of how many 1s I have used using cnt parameter ...power parameter is I think not used in this function

        then I counted recurSum to count the final answer... it uses recurCnt result but using a dp table

        one thing which changes in recurSum is if I have a 1 somewhere .. it have a value of power in its current position .. so how many times this 1 will contribute to the final answer is the value of this 1 which is power multiplied by count of smaller numbers ( in terms of length ) with remaining occurrence of 1s

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    17 months ago, hide # ^ |
    ← Rev. 2  
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    I debugged my code .. but didn't look at yours

    I was calculating two DPs .. count DP and sum DP ... both were 64-bit integers ... I was multiplying 64-bit count DP with some big number in my code which was overflowing.

    I handled modulo for sum DP but had to do it for count DP as well kind of

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17 months ago, hide # |
← Rev. 4  
Vote: I like it 0 Vote: I do not like it

help me find the bug of my code in Problem C : AC x33, WA x5

Click this link to check my code

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17 months ago, hide # |
 
Vote: I like it 0 Vote: I do not like it

The DEF problem in this contest has the same problem in other OJs

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17 months ago, hide # |
 
Vote: I like it +6 Vote: I do not like it

Well, problem C is really harder than D and E.

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17 months ago, hide # |
 
Vote: I like it 0 Vote: I do not like it

Why I got WA and TLE on G here?

I learned how to do this problem here and I used slope trick and std::map.

I hope AtCoder can allow users download test cases again. This is useful for participants and I don't know why AtCoder stop public test cases.

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