ee1e8abd87
* feat(tools): add seed/solution restore script * chore(curriculum): remove empty sections' markers * chore(curriculum): add seed + solution to Chinese * chore: remove old formatter * fix: update getChallenges parse translated challenges separately, without reference to the source * chore(curriculum): add dashedName to English * chore(curriculum): add dashedName to Chinese * refactor: remove unused challenge property 'name' * fix: relax dashedName requirement * fix: stray tag Remove stray `pre` tag from challenge file. Signed-off-by: nhcarrigan <nhcarrigan@gmail.com> Co-authored-by: nhcarrigan <nhcarrigan@gmail.com>
122 lines
2.7 KiB
Markdown
122 lines
2.7 KiB
Markdown
---
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id: 5a23c84252665b21eecc8046
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title: Symmetric difference
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challengeType: 5
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forumTopicId: 16086
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dashedName: symmetric-difference
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---
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# --description--
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Given two [set](https://rosettacode.org/wiki/set)s *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](<https://en.wikipedia.org/wiki/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*).
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# --instructions--
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Write a function that takes two arrays as parameters and returns the symmetric difference. Sort the resultant array before returning it.
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# --hints--
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`symmetricDifference` should be a function.
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```js
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assert(typeof symmetricDifference == 'function');
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```
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`symmetricDifference(["John", "Bob", "Mary", "Serena"], ["Jim", "Mary", "John", "Bob"])` should return an array.
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```js
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assert(
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Array.isArray(
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symmetricDifference(
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['John', 'Bob', 'Mary', 'Serena'],
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['Jim', 'Mary', 'John', 'Bob']
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)
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)
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);
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```
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`symmetricDifference(["John", "Bob", "Mary", "Serena"], ["Jim", "Mary", "John", "Bob"])` should return `["Jim", "Serena"]`.
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```js
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assert.deepEqual(
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symmetricDifference(
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['John', 'Bob', 'Mary', 'Serena'],
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['Jim', 'Mary', 'John', 'Bob']
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),
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['Jim', 'Serena']
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);
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```
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`symmetricDifference([1, 2, 3], [3, 4])` should return `[1, 2, 4]`.
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```js
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assert.deepEqual(symmetricDifference([1, 2, 3], [3, 4]), [1, 2, 4]);
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```
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`symmetricDifference([1, 2, 3, 4, 5], [3, 4, 8, 7])` should return `[1, 2, 5, 7, 8]`.
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```js
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assert.deepEqual(symmetricDifference([1, 2, 3, 4, 5], [3, 4, 8, 7]), [
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1,
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2,
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5,
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7,
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8
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]);
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```
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`symmetricDifference([1, 2, 3, 4, 5, 6, 7, 8], [1, 3, 5, 6, 7, 8, 9])` should return `[2, 4, 9]`.
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```js
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assert.deepEqual(
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symmetricDifference([1, 2, 3, 4, 5, 6, 7, 8], [1, 3, 5, 6, 7, 8, 9]),
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[2, 4, 9]
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);
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```
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`symmetricDifference([1, 2, 4, 7, 9], [2, 3, 7, 8, 9])` should return `[1, 3, 4, 8]`.
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```js
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assert.deepEqual(symmetricDifference([1, 2, 4, 7, 9], [2, 3, 7, 8, 9]), [
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1,
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3,
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4,
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8
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]);
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```
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# --seed--
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## --seed-contents--
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```js
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function symmetricDifference(A, B) {
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}
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```
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# --solutions--
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```js
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function symmetricDifference(A, B) {
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function relative_complement(A, B) {
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return A.filter(function(elem) {
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return B.indexOf(elem) == -1;
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});
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}
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function unique(ary) {
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var u = ary.concat().sort();
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for (var i = 1; i < u.length; ) {
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if (u[i - 1] === u[i]) u.splice(i, 1);
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else i++;
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}
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return u;
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}
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return unique(
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relative_complement(A, B).concat(relative_complement(B, A))
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).sort();
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}
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```
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