/* for a word to be rearrange to palindrome it will need to have even number of letters on all letters or except one letter
aabbcc or aabbc can both be rearrange to palindrome.
make a dictionary storing all the letters, if number of letters are all even or all even except one then return true, else return false.
*/

func isArrangeToPalindrome(string: String) -> Bool{
    guard !string.isEmpty else {
        return false
    }
    var dictionary : [Character : Int] = [:]
    var alreadyHaveOddLetter = false
    for character in string{
        if dictionary[character] != nil{
            dictionary[character]! += 1
        }else {
            dictionary[character] = 1
        }

    }
    for (_, value) in dictionary{
        if value % 2 == 1 && !alreadyHaveOddLetter{
            alreadyHaveOddLetter.toggle()
        } else if value % 2 == 1 && alreadyHaveOddLetter{
            return false
        }
    }
    return true

}


isArrangeToPalindrome(string: "aabbccd") // true
isArrangeToPalindrome(string: "aaabbcc") //true
isArrangeToPalindrome(string: "aaabbbccd") //false