func ransomNote(ransome: String, magazine: String) -> Bool {
    if ransome.isEmpty && magazine.isEmpty {
        return true
    }

    if ransome.isEmpty {
        return true
    }

    if magazine.isEmpty {
        return false
    }

    var freq = [String: Int]()

    for str in magazine {
        if let count = freq[String(str)] {
            freq[String(str)]! = count + 1
        } else {
            freq[String(str)] = 1
        }
    }

    for str in ransome {
        if freq[String(str)] == nil {
            return false
        } else if freq[String(str)] == 0 {
            return false
        }
    }
    return true
}


let val =  ransomNote(ransome: "aa", magazine: "aab")
print(val)