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How do I know if I have NP-hard problems?
A problem is NP-Complete if it is a part of both NP and NP-Hard Problem. A non-deterministic Turing machine can solve NP-Complete problem in polynomial time. NP-Hard problems(say X) can be solved if and only if there is a NP-Complete problem(say Y) that can be reducible into X in polynomial time.
Are there problems harder than NP-hard?
There are complexity classes more “difficult” than NP, for example PSPACE, EXPTIME or EXPSPACE, and all these contain NP-hard but not NP-complete problems. Turing halting problem is undecidable and it belongs to NP-Hard set.
What do you mean by NP-hard problems?
A problem is NP-hard if an algorithm for solving it can be translated into one for solving any NP- problem (nondeterministic polynomial time) problem. NP-hard therefore means “at least as hard as any NP-problem,” although it might, in fact, be harder.
Which of the following is correct for NP-hard problems?
Which of the following problems is not NP complete? Explanation: Hamiltonian circuit, bin packing, partition problems are NP complete problems. Halting problem is an undecidable problem.
Can a problem be NP-hard but not NP?
An NP-hard problem can be beyond NP. The polynomial-time reduction from your X to any problem in NP does not necessarily have a polynomial-time inverse. If the inverse is harder, then the verification is harder. An NP-complete problem, on the other hand, is one that is NP-hard and itself in NP.
What is NP-hard problems explain with examples?
Examples. An example of an NP-hard problem is the decision subset sum problem: given a set of integers, does any non-empty subset of them add up to zero? That is a decision problem and happens to be NP-complete.
Is the NP hard problem NP-hard?
It was proved NP-hard; the proof is given in the famous Garey & Johnson’s book on computational complexity theory. As I did not see how one would have to choose the weights in @Kuifje answer I started thinking about the problem as well and I came to the conclusion that it is NP hard.
Which is the best example of a NP complete problem?
Oh, one more thing, it is believed that if anyone could *ever* solve an “NP-Complete” problem in “P” time, then *all* “NP-complete” problems could also be solved that way by using the same method, and the whole class of “NP-Complete” would cease to exist. The classic example of “NP-Complete” problems is the Traveling Salesman Problem.
Is the graph partitioning problem NP hard or NP complete?
If only a subset of the nodes has to be transferred then this is a graph partitioning problem known: partitioning the vertices of a graph into two subsets such that the weight of the cut between the two subsets is minimum. It was proved NP-hard; the proof is given in the famous Garey & Johnson’s book on computational complexity theory.
What does it mean to solve NP problems in polynomial time?
Thus “NP” means “we can solve it in polynomial time if we can break the normal rules of step-by-step computing”. N on-deterministic method. Since this amazing “N” computer can also do anything a normal computer can, we know that “P” problems are also in “NP”.