faiyaz26's blog

Help on uva 12501 Bulky process of bulk reduction
By faiyaz26, 12 years ago, In English

for this problem UVA 12501

How to solve this problem with segment tree ?

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12 years ago, # |
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something like that. you need to test it, there can be a lot of bugs.

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    12 years ago, # ^ |
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    i have not understood your code!!

    can you give me the idea to solve the problem ?

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      12 years ago, # ^ |
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      all what you need to solve the problem: 1) you need to know how to combine segments. you can find this in my code
      2) google "lazy propagation segment tree".

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        12 years ago, # ^ |
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        i am not new to segment tree..

        I just want to know how to query for this problem. how to combine ? for this interval: [2,5] how to give the ans like this 1*a[2]+2*a[3]+3*a[4]+4*a[5]

        btw thanks for the help so far.. :)

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          12 years ago, # ^ |
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          const TSegment operator + (const TSegment& d) const {
    TSegment res;
    res.toadd = 0;
    res.len = len + d.len;
    res.sum = Sum() + d.Sum();
    res.ansVal = AnsVal() + d.AnsVal() + len * d.Sum();
    return res;
}
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          12 years ago, # ^ |
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          let's divide interval [2, 5] into [2, 3] and [4, 5]
          1*a[2]+2*a[3]+3*a[4]+4*a[5] = 1*a[2]+2*a[3]+ 2*(a[4]+a[5]) +1*a[4]+2*a[5]

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            10 years ago, # ^ |
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            I didn't think of that! Thank you very much for the insight :)

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      12 years ago, # ^ |
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      updated code

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