zalgo

Z-algorithm implemented on haskell's built-in cons-cell-based lists.

A few efficient list-processing functions using the prefix-function, which is defined as:

(prefixFun xs) !! i

is the length of the largest proper substring of xs ending at position i, such that it equals the beginning of xs.

For example:

.-----.             .-----.
a b a c a b a a a b a b a c d
0 0 1 0 1 2 3 1 1 2 3 2 3 4 0
                          ^

The marked substrings are equal, hence the value at the marked location is their length, 4.