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Merge pull request #10505 from abhisekp/feature/sym-diff

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Update Symmetric Difference challenge
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Logan Tegman
2016-09-11 15:13:02 -07:00
committed by GitHub
parent 6fac979fb9 f221bb3163
commit a002d5174c
1 changed files with 6 additions and 2 deletions
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challenges/01-front-end-development-certification/advanced-bonfires.json
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@ -89,7 +89,7 @@
"title": "Symmetric Difference",
"description": [
"Create a function that takes two or more arrays and returns an array of the <dfn>symmetric difference</dfn> (<code>&xutri;</code> or <code>&oplus;</code>) of the provided arrays.",
"Given two sets (for example set <code>A = {1, 2, 3}</code> and set <code>B = {2, 3, 4}</code>), the mathematical term \"symmetric difference\" of two sets is the set of elements which are in either of the two sets, but not in both (<code>A &xutri; B = C = {1, 4}</code>). For every additional symmetric difference you take (say on a set <code>D = {2, 3}</code>), you should get the set with elements which are in either of the two the sets but not both (<code>C &xutri; D = {1, 4} &xutri; {2, 3} = {1, 2, 3, 4}</code>).",
"Given two sets (for example set <code>A = {1, 2, 3}</code> and set <code>B = {2, 3, 4}</code>), the mathematical term \"symmetric difference\" of two sets is the set of elements which are in either of the two sets, but not in both (<code>A &xutri; B = C = {1, 4}</code>). For every additional symmetric difference you take (say on a set <code>D = {2, 3}</code>), you should get the set with elements which are in either of the two the sets but not both (<code>C &xutri; D = {1, 4} &xutri; {2, 3} = {1, 2, 3, 4}</code>). The resulting array must contain only unique values (<em>no duplicates</em>).",
"Remember to use <a href='http://forum.freecodecamp.com/t/how-to-get-help-when-you-are-stuck/19514' target='_blank'>Read-Search-Ask</a> if you get stuck. Try to pair program. Write your own code."
],
"challengeSeed": [
@ -100,11 +100,15 @@
"sym([1, 2, 3], [5, 2, 1, 4]);"
],
"solutions": [
"function sym(args) {\n var index = -1;\n var length = arguments.length;\n var result;\n while (++index < length) {\n var array = arguments[index];\n result = result ? diff(result, array).concat(diff(array, result)) : array;\n }\n return result ? uniq(result) : [];\n}\n\nfunction uniq(arr) {\n var h = Object.create(null);\n var u = [];\n arr.forEach(function(v) {\n if (v in h) return;\n h[v] = true;\n u.push(v);\n });\n return u;\n}\n\nfunction diff(a, b) {\n var h = Object.create(null);\n b.forEach(function(v) {\n h[v] = true; \n });\n return a.filter(function(v) { return !(v in h);});\n}\nsym([1, 2, 3], [5, 2, 1, 4]);\n"
"function sym() {\n var arrays = [].slice.call(arguments);\n return arrays.reduce(function (symDiff, arr) {\n return symDiff.concat(arr).filter(function (val, idx, theArr) {\n return theArr.indexOf(val) === idx \n && (symDiff.indexOf(val) === -1 || arr.indexOf(val) === -1);\n });\n });\n}\nsym([1, 2, 3], [5, 2, 1, 4]);\n"
],
"tests": [
"assert.sameMembers(sym([1, 2, 3], [5, 2, 1, 4]), [3, 4, 5], 'message: <code>sym([1, 2, 3], [5, 2, 1, 4])</code> should return <code>[3, 4, 5]</code>.');",
"assert.equal(sym([1, 2, 3], [5, 2, 1, 4]).length, 3, 'message: <code>sym([1, 2, 3], [5, 2, 1, 4])</code> should contain only three elements.');",
"assert.sameMembers(sym([1, 2, 3, 3], [5, 2, 1, 4]), [3, 4, 5], 'message: <code>sym([1, 2, 3, 3], [5, 2, 1, 4])</code> should return <code>[3, 4, 5]</code>.');",
"assert.equal(sym([1, 2, 3, 3], [5, 2, 1, 4]).length, 3, 'message: <code>sym([1, 2, 3, 3], [5, 2, 1, 4])</code> should contain only three elements.');",
"assert.sameMembers(sym([1, 2, 3], [5, 2, 1, 4, 5]), [3, 4, 5], 'message: <code>sym([1, 2, 3], [5, 2, 1, 4, 5])</code> should return <code>[3, 4, 5]</code>.');",
"assert.equal(sym([1, 2, 3], [5, 2, 1, 4, 5]).length, 3, 'message: <code>sym([1, 2, 3], [5, 2, 1, 4, 5])</code> should contain only three elements.');",
"assert.sameMembers(sym([1, 2, 5], [2, 3, 5], [3, 4, 5]), [1, 4, 5], 'message: <code>sym([1, 2, 5], [2, 3, 5], [3, 4, 5])</code> should return <code>[1, 4, 5]</code>');",
"assert.equal(sym([1, 2, 5], [2, 3, 5], [3, 4, 5]).length, 3, 'message: <code>sym([1, 2, 5], [2, 3, 5], [3, 4, 5])</code> should contain only three elements.');",
"assert.sameMembers(sym([1, 1, 2, 5], [2, 2, 3, 5], [3, 4, 5, 5]), [1, 4, 5], 'message: <code>sym([1, 1, 2, 5], [2, 2, 3, 5], [3, 4, 5, 5])</code> should return <code>[1, 4, 5]</code>.');",