NP-hard problems (Non-deterministic Polynomial-time hard problems) are those problems which are not easier than any problem in NP; in other words, an algorithm for an NP-hard problem can be used to solve any problem in NP by transforming the input in polynomial time. Problems which are in both NP-Hard and NP are known as NP-Complete.
Questions tagged [np-hard]
161 questions
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When NP complete becomes NP hard
Generally, assuming we have a NPC problem. Adding more constraint to it (making it more difficult), is it possible that problem become NPH? I know the difference between NPC and NPH but I don't know how to show that adding new constraints to…
Sara
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Np completeness - Need some clarification in reduction
I wanted some clarification in a concept.
For proving that a problem is NP complete, we use reductions.
Now suppose I have L<=L'. has the reduction to be from L to L' or can I do it it the reverse way also? i.e Can I show that if L can be solved…
Aakash Anuj
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Can it be proven no polynomial algorithm exists for an NP-Complete prob.?
I can't really seem to grasp what it really means to say a problem is NP-Complete. Could anyone help me with the following question?
An NP-complete problem is a problem for which one can prove that an algorithm for solving it in polynomial time does…
StayPuff
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Classifying NP Completeness and Hardness
Choose the correct statement(s):
(A) If X is an NP-complete problem, then X is an NP problem
(B) If X is an NP-complete problem, then X is an NP-hard
(C) Let X be an NP-complete problem. If X can polynomial reduce to a problem Y, then Y is an…
ILiketoaskQuestion
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Multi agent path finding: NP-hard or not?
The question is as such: A 2d grid with obstacles has been given with 'n' robots. The robots can move in the adjacent cell within one time-tick. There are multiple constraints on robots like they cannot be in the same cell at the same time. However,…
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NP, NP-Complete, NP-Hard questions
I am studying NP and I can't understand how can I solve the below questions. I would like to know the strategy that I should use to be able to solve this kind of problems.
The question is:
Assume A and B are specific decision problems and that f is…
Khaled Omar
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Maximizing the overall sum of K disjoint and contiguous subsets of size L among N positive numbers
I'm trying to find an algorithm to find K disjoint, contiguous subsets of size L of an array x of real numbers that maximize the sum of the elements.
Spelling out the details, X is a set of N positive real numbers:
X={x[1],x[2],...x[N]} where…
Raman
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np-hard -closure
if l1 is in NP-HARD, so for every L2!=empty set, l1*l2 is in np-hard.
when:
l1*l2={(w1,w2) , w1 in L1 and w2 in L2}
Is it true or false and why?
I can't approve it but I also don't find counter example.
user1462787
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NP-hard algorithm
I'm working on a NP-hard problem algorithm (like hand seller problem) and I can't find the proper algorithm. I will appreciate if anyone can help me with it. We have a (x,y) matrix, there is a robot in the (n,m) block and there are some rubbish in…
ali khorshidi rozbahani
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Is there any NP example that we can get an answer in polynomial time？
I just read NP and P on wikipedia, I have two questions:
Can we solve an NP example in polynomial time ?
Is there any NP example that we can get an answer in polynomial time？
Tracy Da
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Java: Traveling Salesman - Found polynomial algorithm
Edit: An improvement to this algorithm been found. Your are welcome to see it.
This question is the an improvement of my old question. Now I want to show you Java code sample, and explain my algorithm in more details.
I think that I found a…
Ilya Gazman
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