2.7 KiB
id | title | challengeType | forumTopicId | dashedName |
---|---|---|---|---|
5a23c84252665b21eecc8046 | Symmetric difference | 5 | 16086 | symmetric-difference |
--description--
Given two sets A and B, compute (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 \\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).
--instructions--
Write a function that takes two arrays as parameters and returns the symmetric difference. Sort the resultant array before returning it.
--hints--
symmetricDifference
should be a function.
assert(typeof symmetricDifference == 'function');
symmetricDifference(["John", "Bob", "Mary", "Serena"], ["Jim", "Mary", "John", "Bob"])
should return an array.
assert(
Array.isArray(
symmetricDifference(
['John', 'Bob', 'Mary', 'Serena'],
['Jim', 'Mary', 'John', 'Bob']
)
)
);
symmetricDifference(["John", "Bob", "Mary", "Serena"], ["Jim", "Mary", "John", "Bob"])
should return ["Jim", "Serena"]
.
assert.deepEqual(
symmetricDifference(
['John', 'Bob', 'Mary', 'Serena'],
['Jim', 'Mary', 'John', 'Bob']
),
['Jim', 'Serena']
);
symmetricDifference([1, 2, 3], [3, 4])
should return [1, 2, 4]
.
assert.deepEqual(symmetricDifference([1, 2, 3], [3, 4]), [1, 2, 4]);
symmetricDifference([1, 2, 3, 4, 5], [3, 4, 8, 7])
should return [1, 2, 5, 7, 8]
.
assert.deepEqual(symmetricDifference([1, 2, 3, 4, 5], [3, 4, 8, 7]), [
1,
2,
5,
7,
8
]);
symmetricDifference([1, 2, 3, 4, 5, 6, 7, 8], [1, 3, 5, 6, 7, 8, 9])
should return [2, 4, 9]
.
assert.deepEqual(
symmetricDifference([1, 2, 3, 4, 5, 6, 7, 8], [1, 3, 5, 6, 7, 8, 9]),
[2, 4, 9]
);
symmetricDifference([1, 2, 4, 7, 9], [2, 3, 7, 8, 9])
should return [1, 3, 4, 8]
.
assert.deepEqual(symmetricDifference([1, 2, 4, 7, 9], [2, 3, 7, 8, 9]), [
1,
3,
4,
8
]);
--seed--
--seed-contents--
function symmetricDifference(A, B) {
}
--solutions--
function symmetricDifference(A, B) {
function relative_complement(A, B) {
return A.filter(function(elem) {
return B.indexOf(elem) == -1;
});
}
function unique(ary) {
var u = ary.concat().sort();
for (var i = 1; i < u.length; ) {
if (u[i - 1] === u[i]) u.splice(i, 1);
else i++;
}
return u;
}
return unique(
relative_complement(A, B).concat(relative_complement(B, A))
).sort();
}