fun main(args: Array<String>) {
    /*
    re-arrange to key/pairs of original to match target
    make sure no value is assigned to two keys in original at the same time.

    You'd start with swapping original[2] with with placeholdingChar, such that placeholdingChar is now 'a'.
    Then you'd lookup 'target' to see at which index 'a' belongs. Then you'd swap the value of that index in
    'original' with 'a', and lookup target to see where that belongs.

    Proceed until all values are with their correct key.
    */
}

var placeholdingChar = "f"

val original = mutableMapOf(1 to "c",
                     2 to "d",
                     3 to "a",
                     4 to "e",
                     5 to "b")

val target = mapOf(1 to "a",
                   2 to "b",
                   3 to "c",
                   4 to "d",
                   5 to "e")