Given a dictionary and a list of letters find all valid words that can be built with the letters

Question

The brute force way can solve the problem in O(n!), basically calculating all the permutations and checking the results in a dictionary. I am looking for ways to improve the com

Answer 1

Swift 3

 func findValidWords(wordsList: [String] , string: String) -> [String]{

    let charCountsDictInTextPassed = getCharactersCountIn(string: string)
    var wordsArrayResult: [String] = []

    for word in wordsList {

        var canBeProduced = true
        let currentWordCharsCount = getCharactersCountIn(string: word)

        for (char, count) in currentWordCharsCount {
            if let charCountInTextPassed = charCountsDictInTextPassed[char], charCountInTextPassed >= count {
                continue
            }else{
                canBeProduced = false
                break
            }
        }// end for

        if canBeProduced {
            wordsArrayResult.append(word)
        }//end if
    }//end for
        return wordsArrayResult
}


// Get the count of each character in the string
func getCharactersCountIn(string: String) -> [String: Int]{
    var charDictCount:[String: Int] = [:]
    for char in string.characters {
        if let count = charDictCount[String(char)] {
            charDictCount[String(char)] = count + 1
        }else{
            charDictCount[String(char)] = 1
        }
    }//end for
    return charDictCount
}