Concepts3

Convolution turns local pairwise combinations (like matching characters or adding two dice) into a single fast transform–multiply–inverse pipeline.

Subset Sum Convolution (often called Subset Convolution) computes C[S] by summing A[T]×B[U] over all disjoint pairs T and U whose union is S.

Sum over Subsets (SOS) DP lets you compute F[mask] = sum of A[submask] over all submasks in O(n 2^n) instead of O(3^n).