Problem Statement

Given two sets A and B, compute

( A ∖ B ) ∪ ( B ∖ A ) .

{\displaystyle (A\setminus B)\cup (B\setminus A).}

That is, enumerate the items that are in A or B but not both. This set is called the symmetric difference of A and B. In other words:

( A ∪ B ) ∖ ( A ∩ B )

{\displaystyle (A\cup B)\setminus (A\cap B)}

(the set of items that are in at least one of A or B minus the set of items that are in both A and B). Optionally, give the individual differences (

A ∖ B

{\displaystyle A\setminus B}

and

B ∖ A

{\displaystyle B\setminus A}

) as well.

Let's start with the solution:

/* builtin */
symmdifference({"John", "Bob", "Mary", "Serena"},
               {"Jim", "Mary", "John", "Bob"});
{"Jim", "Serena"}