Algorithm for checking if a string was built from a list of substrings

Question

You are given a string and an array of strings. How to quickly check, if this string can be built by concatenating some of the strings in the array?

This is a theoretica

Answer 1

Inspired by @cnicutars answer:

• function Possible(array A, string s)
  • If s is empty, return true.
  • compute the array P of all strings in A that are a prefix of s.
  • If P is empty, return false.
  • for each string p in P:
    • if Possible(A with p removed, s with prefix p removed) return true
  • return false