Invitation to Coders' Legacy 2020 (Rated for all)

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Hoping the same

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While submitting solution for 3rd problem, there was some server issue so i had to retry 2 times. Now its showing I made 3 correct Ac submission for 3rd. All submissions are identical. Did I get any penalty for that? If yes, Can anything be done about it?

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No, you’ll not get a penalty for AC submissions.

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You could have checked in “My submissions” to make sure if you’ve submitted or not.

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Nice problems! Waiting for the editorials

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Questions were really awesome…Loved solving them :smile:

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Amazing set of questions, really enjoyed it. :v:

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31

How to solve 4th (CLLEXO) ?

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Can someone suggest how to solve the 4th problem. I did try using DP but that was giving TLE as I was comparing the strings in O(N+M-1) and my DP was (NM) so total time complexity becomes O((NM)*(N+M-1)). Is there some algorithm involved in this comparison that I might be unaware of?

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I will be more than thankful to anyone who will tell the mistake in my solution for the 4th question. There is mp a silly mistake somewhere but I am just not able to figure that out.

Thanks in advance :slight_smile:

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Can you explain your approach to this problem please? I think it will be really helpful for all of us.

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Why did constraints have to be so high in… every problem? I had to struggle very hard to squeeze CLUNQUE. And anyone who doesn’t use C++ would be totally screwed.

6 Likes
36

Actually the prompt said it was not uploaded, so I assumed its not submitted. My bad.

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It’s a WA, I will explain though
Following observations-

  1. The question is basically this- find lexicographically smallest string going from (0,0) to (n-1,m-1) by only moving right or down but we can - not go in a cell marked #.
  2. The answer string will be of length n+m-1

I did a DFS from (0,0). For both it’s children, I am checking if they are valid ( They are not # and there is a path from them to (n-1,m-1)). Now assume they are valid. The current character will come at the position row+col (if it will come) in the answer. So I am marking that For (current level,char) the next char should be the min of chars of it’s valid children.

After this just following the path from (0,0) to get the answer.

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indeed constraints were a pain.

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Complexity of both of my last 2 submissions of third problem (CLBRKT) were O(qlog(|s|)). The only difference between two submissions was a cin and scanf only for the input of number of test cases T.

The one with cin got TLE Submission
Other one with scanf got AC Submission

I am not sure why this happened and it costed me 1 hour of penalty time.

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I haven’t looked too hard at your code. But from your logic, I see what looks like a mistake. How do you break ties?

Please ignore this, I’m high

2 Likes
41

Expected was O(|s|+Q) I guess , so you are lucky that it got passed.

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Maybe, I spent last hour trying to figure out O(|S| + Q) solution, but fortunately got accepted :smiley:

1 Like
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Why couldn’t PyPy2 pass even problem 1?