Algorithms can be classified by their order of growth. - **Constant time** algorithms run is constant time. - **Log time** algorithms run in $\log n$ or $n \log n$ or variations thereof. - **Polynomial time** algorithms are of the form $n^c$, such as $n^2$ ([[insertion sort]]), $n^3$ (some matrix procedures), and $n^4$. - **Polylog time** algorithms combine polynomials and log times. - **Exponential time** algorithms are of the form $c^n$. - More complex algorithms include $n!$ and some of the class **non-elementary algorithms**.