# Rosalind: BA5C — Find a Longest Common Subsequence of Two Strings
# https://rosalind.info/problems/ba5c/
#
# Given: Two strings.
# Return: A longest common subsequence.

let s = "AACCTTGG"
let t = "ACACTGTGA"

# lcs is a builtin. There is generally more than one longest common
# subsequence — the sample shows AACTGG, this returns another of the same
# length — so the assertion checks the length and that it really is a
# subsequence of both, which is what the problem asks for.
let common = lcs(s, t)

println("Result:   " + common + "  (length " + str(len(common)) + ")")
println("Expected: AACTGG, or any other subsequence of length 6")

fn test_ba5c_longest_common_subsequence() {
    assert len(common) == 6, "BA5C: expected length 6, got " + str(len(common))
    assert is_subsequence(common, s), "BA5C: not a subsequence of s"
    assert is_subsequence(common, t), "BA5C: not a subsequence of t"
    assert len(lcs("AACTGG", t)) == 6, "BA5C: the sample answer should also be length 6"
}