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126 lines
2.7 KiB
Markdown
126 lines
2.7 KiB
Markdown
---
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id: 5a23c84252665b21eecc8046
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title: 对称差异
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challengeType: 1
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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 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*).
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例如：
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对于集 `A = [1, 2, 3]`, 和 `B = [1, 3, 4]`, *A* 和 *B* 的对称差为 `[2, 4]`。
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# --instructions--
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编写一个函数，将两个数组作为参数并返回对称差。 在返回之前对结果数组进行排序。
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# --hints--
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`symmetricDifference` 应该是一个函数。
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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"])` 应该返回一个数组。
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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"])` 应该返回 `["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])` 应该返回 `[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])` 应该返回 `[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])` 应该返回 `[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])` 应该返回 `[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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