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Similarly, a polynomial time algorithm is not always practical. If its running time is, say, ''n''¹⁵, it is unreasonable to consider it efficient and it is still useless except on small instances. Indeed, in practice even ''n''³ or ''n''² algorithms are often impractical on realistic sizes of problems.

Similarly, a polynomial time algorithm is not always practical. If its running time is, say, ''n''¹⁵, it is unreasonable to consider it efficient and it is still useless except on small instances. Indeed, in practice even ''n''³ or ''n''² algorithms are often impractical on realistic sizes of problems.

类似地，多项式时间算法并不总是实用的。如果它的运行时间是，比如说“n”¹⁵，那么认为它是有效的是不合理的，而且除了在小实例上，它仍然是无用的。实际上，在实践中，即使是''n''³ 或 ''n''² 算法对于实际大小的问题往往是不切实际的。

类似地，多项式时间算法并不总是实用的。如果它的运行时间是，比如说“n”¹⁵，那么认为它有效是不合理的，而且除了在小的实例上，它仍旧是无用的。实际上，在实践中，即使是''n''³ 或 ''n''² 算法对于实际大小的问题也往往是不切实际的。

==Continuous complexity theory连续复杂性理论==

==Continuous complexity theory连续复杂性理论==