unique check.scala

import scala.collection.mutable.HashMap

object CheckUnique {

    def main (args: Array[String]) {
    
        val str = "abc"
        val res = checkUnique(str)
        println(str + "->" + res.toString)

        val str2 = "aab"
        val res2 = checkUnique(str2)
        println(str2 + "->" + res2.toString)

    }

    def checkUnique(str: String): Boolean = {
        val uMap: HashMap[Char, Boolean] = new HashMap()

        str.map(_.toChar).foreach {c =>
            uMap.get(c) match {
                case Some(true)   => return false
                case Some(false)  => return false
                case None         => uMap.put(c, true)
            }
        }

        return true
    }
}