Finds valid words in a dictionary based on all permutations of valid characters

WordFinder.scala

import scala.io.Source

object WordFinder {

  // All permutations of the characters in the string
  def permutations(s: String): List[String] = s.toSeq.permutations.map(_.unwrap).toList

  // All distinct substrings obtained by removing one character from the original string
  def subsets(s: String): List[String] = {
    if (s.length == 1) List(s) else {
      for (i <- 0 until s.length) yield removeChar(s, i)
    }.toList.distinct
  }

  // Removes the i-th character from the string
  def removeChar(s: String, i: Int): String = s.take(i).concat(s.drop(i + 1))


  // All distinct permutations with length `minLength` or more of the string `s`
  def allPermutation(s: String, minLength: Int): List[String] = {
    if (s.length == minLength) permutations(s) else {
      permutations(s) ++ subsets(s).flatMap(allPermutation(_, minLength)).distinct
    }
  }

  // Iterates over all lines in the dictionary
  def wordFile(): Iterator[String] = Source.fromInputStream(getClass.getResourceAsStream("/word.list")).getLines()

  // List of permutations of the string `s` or its substrings of length >= `minlength` that exist in the dictionary
  def solve(s: String, minLength: Int): List[String] = {
    val combinations = allPermutation(s, minLength).toSet
    wordFile().filter(combinations.contains).toList
  }
}

Link to word.list file.