For s1 and s2, divide each into a sequence of single alphabet strings and digital strings. The problem now becomes comparing if two sequences are equal.

A single alphabet string has no variation, but a digital string has variations. For example: "124" can be interpreted as 1+2+4, 12+4, 1+24, and 124 wildcard characters.

There are four kinds of comparisons: a single alphabet vs another; a single alphabet vs a number, a number vs a single alphabet, and a number vs another number. In the case of a number vs another (a single alphabet or a number), can you decrease the number by the min length of both?

There is a recurrence relation in the search which ends when either a single alphabet != another, or one sequence ran out, or both sequences ran out.