104 lines
7.7 KiB
Markdown
104 lines
7.7 KiB
Markdown
---
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id: 5a23c84252665b21eecc8024
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title: State name puzzle
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challengeType: 5
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---
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## Description
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<section id='description'>
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<b>Background</b>
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This task is inspired by <a href="http://drdobbs.com/windows/198701685">Mark Nelson's DDJ Column "Wordplay"</a> and one of the weekly puzzle challenges from Will Shortz on NPR Weekend Edition [http://www.npr.org/templates/story/story.php?storyId=9264290] and originally attributed to David Edelheit.
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The challenge was to take the names of two U.S. States, mix them all together, then rearrange the letters to form the names of two <i>different</i> U.S. States (so that all four state names differ from one another).
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What states are these?
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The problem was reissued on <a href="https://tapestry.tucson.az.us/twiki/bin/view/Main/StateNamesPuzzle">the Unicon Discussion Web</a> which includes several solutions with analysis. Several techniques may be helpful and you may wish to refer to <a href="https://en.wikipedia.org/wiki/Goedel_numbering">Gödel numbering</a>, <a href="https://en.wikipedia.org/wiki/Equivalence_relation">equivalence relations</a>, and <a href="https://en.wikipedia.org/wiki/Equivalence_classes">equivalence classes</a>. The basic merits of these were discussed in the Unicon Discussion Web.
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A second challenge in the form of a set of fictitious new states was also presented.
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<b>Task:</b>
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Write a function to solve the challenge for the given array of names of states. The function should return an array. Each element should be an object in this form: {"from":[],"to":[]}. The "from" array should contain the original names and the "to" array should contain the resultant names.
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</section>
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## Instructions
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<section id='instructions'>
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</section>
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## Tests
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<section id='tests'>
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``` yml
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tests:
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- text: <code>solve</code> should be a function.
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testString: assert(typeof solve == 'function', '<code>solve</code> should be a function.');
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- text: <code>solve(["New Mexico", "New York", "North Carolina ", "North Dakota", "Ohio", "Oklahoma", "Oregon", "Pennsylvania", "Rhode Island", "South Carolina", "South Dakota"])</code> should return a array.
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testString: assert(Array.isArray(solve(["New Mexico", "New York", "North Carolina ", "North Dakota", "Ohio", "Oklahoma", "Oregon", "Pennsylvania", "Rhode Island", "South Carolina", "South Dakota"])), '<code>solve(["New Mexico", "New York", "North Carolina ", "North Dakota", "Ohio", "Oklahoma", "Oregon", "Pennsylvania", "Rhode Island", "South Carolina", "South Dakota"])</code> should return a array.');
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- text: '<code>solve(["New Mexico", "New York", "North Carolina ", "North Dakota", "Ohio", "Oklahoma", "Oregon", "Pennsylvania", "Rhode Island", "South Carolina", "South Dakota"])</code> should return <code>[{ from: ["North Carolina ", "South Dakota"], to: ["North Dakota", "South Carolina"] }]</code>.'
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testString: assert.deepEqual(solve(["New Mexico", "New York", "North Carolina ", "North Dakota", "Ohio", "Oklahoma", "Oregon", "Pennsylvania", "Rhode Island", "South Carolina", "South Dakota"]), [{ from:["North Carolina ", "South Dakota"], to:["North Dakota", "South Carolina"] }], '<code>solve(["New Mexico", "New York", "North Carolina ", "North Dakota", "Ohio", "Oklahoma", "Oregon", "Pennsylvania", "Rhode Island", "South Carolina", "South Dakota"])</code> should return <code>[{ from:["North Carolina ", "South Dakota"], to:["North Dakota", "South Carolina"] }]</code>.');
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- text: '<code>solve(["New York", "New Kory", "Wen Kory", "York New", "Kory New", "New Kory"])</code> should return <code>[{ from: ["New Kory", "New York"], to: ["Wen Kory", "York New"] }, { from: ["New Kory", "New York"], to: ["Kory New", "Wen Kory"] }, { from: ["New Kory", "New York"], to: ["Kory New", "York New"] }, { from: ["New York", "Wen Kory"], to: ["New Kory", "York New"] }, { from: ["New York", "Wen Kory"], to: ["Kory New", "New Kory"] }, { from: ["New York", "Wen Kory"], to: ["Kory New", "York New"] }, { from: ["New York", "York New"], to: ["New Kory", "Wen Kory"] }, { from: ["New York", "York New"], to: ["Kory New", "New Kory"] }, { from: ["New York", "York New"], to: ["Kory New", "Wen Kory"] }, { from: ["Kory New", "New York"], to: ["New Kory", "Wen Kory"] }, { from: ["Kory New", "New York"], to: ["New Kory", "York New"] }, { from: ["Kory New", "New York"], to: ["Wen Kory", "York New"] }, { from: ["New Kory", "Wen Kory"], to: ["Kory New", "York New"] }, { from: ["New Kory", "York New"], to: ["Kory New", "Wen Kory"] }, { from: ["Kory New", "New Kory"], to: ["Wen Kory", "York New"] }]</code>.'
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testString: assert.deepEqual(solve(["New York", "New Kory", "Wen Kory", "York New", "Kory New", "New Kory"]), [{ from:["New Kory", "New York"], to:["Wen Kory", "York New"] }, { from:["New Kory", "New York"], to:["Kory New", "Wen Kory"] }, { from:["New Kory", "New York"], to:["Kory New", "York New"] }, { from:["New York", "Wen Kory"], to:["New Kory", "York New"] }, { from:["New York", "Wen Kory"], to:["Kory New", "New Kory"] }, { from:["New York", "Wen Kory"], to:["Kory New", "York New"] }, { from:["New York", "York New"], to:["New Kory", "Wen Kory"] }, { from:["New York", "York New"], to:["Kory New", "New Kory"] }, { from:["New York", "York New"], to:["Kory New", "Wen Kory"] }, { from:["Kory New", "New York"], to:["New Kory", "Wen Kory"] }, { from:["Kory New", "New York"], to:["New Kory", "York New"] }, { from:["Kory New", "New York"], to:["Wen Kory", "York New"] }, { from:["New Kory", "Wen Kory"], to:["Kory New", "York New"] }, { from:["New Kory", "York New"], to:["Kory New", "Wen Kory"] }, { from:["Kory New", "New Kory"], to:["Wen Kory", "York New"] }], '<code>solve(["New York", "New Kory", "Wen Kory", "York New", "Kory New", "New Kory"])</code> should return <code>[{ from:["New Kory", "New York"], to:["Wen Kory", "York New"] }, { from:["New Kory", "New York"], to:["Kory New", "Wen Kory"] }, { from:["New Kory", "New York"], to:["Kory New", "York New"] }, { from:["New York", "Wen Kory"], to:["New Kory", "York New"] }, { from:["New York", "Wen Kory"], to:["Kory New", "New Kory"] }, { from:["New York", "Wen Kory"], to:["Kory New", "York New"] }, { from:["New York", "York New"], to:["New Kory", "Wen Kory"] }, { from:["New York", "York New"], to:["Kory New", "New Kory"] }, { from:["New York", "York New"], to:["Kory New", "Wen Kory"] }, { from:["Kory New", "New York"], to:["New Kory", "Wen Kory"] }, { from:["Kory New", "New York"], to:["New Kory", "York New"] }, { from:["Kory New", "New York"], to:["Wen Kory", "York New"] }, { from:["New Kory", "Wen Kory"], to:["Kory New", "York New"] }, { from:["New Kory", "York New"], to:["Kory New", "Wen Kory"] }, { from:["Kory New", "New Kory"], to:["Wen Kory", "York New"] }]</code>.');
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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function solve (input) {
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// Good luck!
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}
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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function solve (input) {
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var orig = {};
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input.forEach(function(e) {
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orig[e.replace(/\s/g, "").toLowerCase()] = e;
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})
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input = Object.keys(orig)
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var map = {};
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for (var i = 0; i < input.length - 1; i++) {
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var pair0 = input[i];
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for (var j = i + 1; j < input.length; j++) {
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var pair = [pair0, input[j]];
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var s = pair0 + pair[1];
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var key = s.split("").sort();
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var val = map[key] ? map[key] : [];
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val.push(pair);
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map[key] = val;
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}
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}
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var result = [];
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Object.keys(map).forEach((key) => {
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for (var i = 0; i < map[key].length - 1; i++) {
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var a = map[key][i];
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for (var j = i + 1; j < map[key].length; j++) {
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var b = map[key][j];
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if ((new Set([a[0], b[0], a[1], b[1]])).size < 4)
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continue;
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var from = [orig[a[0]], orig[a[1]]].sort()
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var to = [orig[b[0]], orig[b[1]]].sort()
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result.push({
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from,
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to
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})
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}
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}
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});
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return result;
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}
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```
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</section> |