sort: Sorting and searching: quick sort, radix sort and binary search.
graph: Searching directed graphs, mostly to find combinatorial objects.
mod: Modular arithmetics and number theory.
gf2n: Binary polynomials, finite fields GF(2^n) and shift registers.
perm: Routines for computations with permutations.
fft: Fast Fourier and Walsh transform.
bits: Bit fiddling routines.
arith: Arithmetical algorithms like CORDIC and powering.
comb: Combinatorial objects like combinations, permutations, Gray codes, partitions and necklaces.
seq: Integer sequences by OEIS number.
ds: Data structures like FIFO, heap and deque.