object AlphanumericSorter {
/**
* Assigns a sorting priority (category rank) to each character type.
* Lower rank means the character group comes earlier.
* * 1. lowercase letters (a-z) -> 0
* 2. uppercase letters (A-Z) -> 1
* 3. odd digits (1,3,5,7,9) -> 2
* 4. even digits (0,2,4,6,8) -> 3
*/
def getCategoryRank(c: Char): Int = {
if (c.isLower) 0
else if (c.isUpper) 1
else if (c.isDigit) {
// (c - '0') converts a digit Char to its integer representation
if ((c - '0') % 2 != 0) 2 else 3
}
else 4 // Fallback for any non-alphanumeric characters
}
/**
* Sorts the input string based on the custom rules:
* lowercase -> uppercase -> odd digits -> even digits.
* Within each category, characters are sorted in their natural ascending order.
*/
def sortString(s: String): String = {
// We leverage Scala's sortBy which accepts a function returning a Tuple.
// Tuples are compared element-by-element:
// First by category rank, then by the character's ASCII/Unicode value.
s.sortBy(c => (getCategoryRank(c), c))
}
def main(args: Array[String]): Unit = {
val input = "a2B3cD8f1Z0"
val result = sortString(input)
println(s"Sorted result: $result")
}
}
/*
run:
Sorted result: acfBDZ13028
*/
