ZPP (Complexity)

High Quality Content by WIKIPEDIA articles! In complexity theory, ZPP (zero-error probabilistic polynomial time) is the complexity class of problems for which a probabilistic Turing machine exists with these properties: It always returns the correct YES or NO answer., The running time is polynomial on average for any input. In other words, the algorithm is allowed to flip a truly-random coin while it is running. It always returns the correct answer. (Such an algorithm is called a Las Vegas algorithm.) For a problem of size n, there is some polynomial p(n) such that the average running time will be less than p(n), even though it might occasionally be much longer.... Mehr