Suppose a polynomial time algorithm is discovered that correctly computes the…

2014

Suppose a polynomial time algorithm is discovered that correctly computes the largest clique in a given graph. In this scenario, which one of the following represents the correct Venn diagram of the complexity classes P, NP and NP Complete (NPC)?

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Key idea: CLIQUE is an NP-Complete problem.

  • If there exists a polynomial-time algorithm for an NP-Complete problem, then every problem in NP can be solved in polynomial time (because every NP problem reduces in polynomial time to any NP-Complete problem).

  • Therefore P = NP: the class of problems solvable in polynomial time equals the class verifiable in polynomial time.

  • When P = NP, NP-Complete problems are also in P, so NP-Complete, NP, and P all collapse to the same set.

Conclusion: The correct Venn diagram is a single circle representing P = NP = NP-Complete.

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