Longest Common Subsequence in Elixir

Welcome to the Longest Common Subsequence in Elixir page! Here, you’ll find the source code for this program as well as a description of how the program works.

Current Solution

defmodule LongestCommonSubsequence do
  def main() do
    lcs = solve(System.argv())
    IO.puts("#{lcs}")
  end

  def solve([as, bs]) when is_bitstring(as) and is_bitstring(bs) do
    lcs(parse_string_to_list_integer(as), parse_string_to_list_integer(bs)) |> Enum.join(", ")
  end

  def solve(_) do
    print_usage()
  end

  def print_usage() do
    ~s(Usage: please provide two lists in the format "1, 2, 3, 4, 5")
  end

  def lcs([], _) do
    []
  end

  def lcs(_, []) do
    []
  end

  def lcs([a | as], [b | bs]) when a == b do
    [a] ++ lcs(as, bs)
  end

  def lcs([a | as], [b | bs]) do
    longest(lcs(as, [b | bs]), lcs([a | as], bs))
  end

  def longest(l1, l2) do
    if Enum.count(l1) > Enum.count(l2) do
      l1
    else
      l2
    end
  end

  def parse_string_to_list_integer(xs) do
    xs
    |> String.trim()
    |> String.split(",")
    |> Enum.map(&String.to_integer(String.trim(&1)))
  end
end

LongestCommonSubsequence.main()

Longest Common Subsequence in Elixir was written by:

• Ann
• Jeremy Grifski

If you see anything you’d like to change or update, please consider contributing.

Note: The solution shown above is the current solution in the Sample Programs repository as of Oct 16 2019 00:49:15. The solution was first committed on Oct 14 2019 07:19:41. As a result, documentation below may be outdated.

How to Implement the Solution

No ‘How to Implement the Solution’ section available. Please consider contributing.

How to Run the Solution

No ‘How to Run the Solution’ section available. Please consider contributing.