uniqueChars.kt

    fun isUniqueChars(str: String): Boolean {
        if (str.length > 256) return false

        var checker: Int = 0
        for (idx in 0..(str.length-1)) {
            val value: Int = str[idx] - 'a'
            if ((checker and (1 shl value)) > 0) {
                return false
            }
            checker = checker or (1 shl value)
        }

        return true
    }