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## Discussion of Problem 1648. Yachts

What is a right algorithm to that problem?
Posted by Asyamov Igor 26 Oct 2008 11:53
Is it greedy???
Yes (-)
Posted by Ivan 26 Oct 2008 12:14
Re: What is a right algorithm to that problem?
Posted by svr 26 Oct 2008 19:56
Greedy only? I think.
I don't solve else but think that next algo is right:
1. maximal production =d in all n periods;
2. Greedy approach :satisfy first demand as fully as possible;
3. If we have residue in last period equal to k
diminish by k residues in previous periods until it is possible
4. Sum final residues along all periods.

Edited by author 26.10.2008 20:52
Re: What is a right algorithm to that problem?
Posted by Asyamov Igor 26 Oct 2008 20:37
My algo is the same as your! (but still wa 15) :-(
Re: What is a right algorithm to that problem?
Use DP
Re: What is a right algorithm to that problem?
Posted by svr 26 Oct 2008 21:43
You definitely need reading math eco theory
optimal store managing(Taha  a.s.o.)
P.S.I also have WA14. First number of output I guarantee but
the second need more delicate algo.
Re: What is a right algorithm to that problem?
Posted by Asyamov Igor 26 Oct 2008 21:47
may be your problem with the type of the second number(it should be __int64)???
*
Posted by Maxim Dvoynishnikov (Dnipropetrovsk SU) 27 Oct 2008 01:32
I have WA49 with greedy and restroring.
Re: *
Posted by double 27 Oct 2008 06:17
use int64(long long) ,then you'll get AC.
Re: What is a right algorithm to that problem?
Posted by svr 27 Oct 2008 09:21
Yuare right!
With __int 64 AC.
All data seemed fitted in int type.

Edited by author 27.10.2008 09:21
Re: What is a right algorithm to that problem?
Posted by Asyamov Igor 27 Oct 2008 18:02
Are you got AC with your algo or you had chaged it???
Re: What is a right algorithm to that problem?
Posted by Asyamov Igor 27 Oct 2008 18:16

Edited by author 28.10.2008 14:51
Re: What is a right algorithm to that problem?
Posted by svr 27 Oct 2008 18:54
I considered stored values backward more attentievely
according with alg:
store[i-1]=max(store[i]+sell[i-1]-d,0)
store[n]:=0;
i=n..1
where sell[i-1] array of greedy selling on the first stage.
Re: What is a right algorithm to that problem?
Posted by Asyamov Igor 28 Oct 2008 15:39
Accepted!!!!!!
this test help me find my bug...
in:
5 5
3 1 20 3 10
out: 25 10

and now,after accepted, could somebody, who solved this problem with DP, sent to me your solution?
my mail: asyamov@mail.ru

Edited by author 28.10.2008 16:18
Re: What is a right algorithm to that problem?
Posted by lql1993 2 Dec 2008 16:30
I think greedy can work well.
Re: What is a right algorithm to that problem?
Posted by Vit Demidenko 27 Aug 2010 20:27
I don'n understand, how to solve this problem whith DP or greedy. I solve with RMQ.