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zeref_dragoneel's blog

XXXXXXXX solution

By zeref_dragoneel, history, 7 years ago, In English

Problem link: http://www.spoj.com/problems/XXXXXXXX/

Solution Link: http://ideone.com/Myb8M6

Can someone help me debug my solution? I am trying to use segtree + treap in the code.

Thanks.

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7 years ago, # |
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Got the mistake. It was int -> long long mistake.

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    7 years ago, # ^ |
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    Can you please explain your approach.

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      7 years ago, # ^ |
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      I have used the approach explained in the comment http://codeforces.com/blog/entry/10508?#comment-158835

      while updating i for A[i], I add the value A[i] to the point representing (i, left[i]) where left[i] denotes the greatest j s.t. A[j] == A[i] & j < i. If no such j exists, then left[i] = 0.

      Now for query, I found the sum in (L,0) to (R,L-1) both included.

      Updated code with int -> long long correction: http://ideone.com/sJMdlW

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        7 years ago, # ^ |
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        Thanks for the link.I guess instead of using treap we can also use square root decomposition with a bit in each block.

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          7 years ago, # ^ |
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          Yes, that should also work but I am not sure whether it will pass the time limit (Q * sqrtN * logN solution) as spoj is relatively more time-strict than any other sites I know.

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7 years ago, # |
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    7 years ago, # ^ |
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    Well -3 seems like downvoted to me...

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      7 years ago, # ^ |
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      It was 0 when I came and we all know that -3 is nothing compared to what a green coder would receive.

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    7 years ago, # ^ |
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    Well, I did not personally ask you or anyone to debug the code.

    I only posted it as a question. So, if someone will be available to debug it, he/she will and will tell me my mistake. You or Anyone for that matter had any obligation to see the code and try to find a bug.

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