RosettaCodeData/Task/Last-letter-first-letter/JavaScript/last-letter-first-letter.js

91 lines
2.6 KiB
JavaScript

/**
* Find the letter the word ends on
* @param {string} word
* @returns {string}
*/
const endsWith = word => word[word.length - 1];
/**
* Remove the used elements from the candidate elements
* @param {Array<string>} words Candidate words
* @param {Array<string>} used Used words
* @returns {*}
*/
const getCandidates = (words, used) => words.filter(e => !used.includes(e));
/**
* Build a map of letters to words that start with that letter
* @param {Array<string>} words
* @returns {Map<string, Array<string>>}
*/
const buildLookup = words => {
const lookup = new Map();
words.forEach(e => {
const start = e[0];
lookup.set(start, [...(lookup.get(start) || []), e]);
});
return lookup;
};
/**
* Main function
* @param {Array<string>} names
*/
const findPaths = names => {
const t0 = process.hrtime();
console.log('Checking:', names.length, 'names');
const lookup = buildLookup(names);
let maxNum = 0;
let maxPaths = [];
const parseResult = arr => {
if (typeof arr[0] === 'object') {
arr.forEach(el => parseResult(el))
} else {
if (arr.length > maxNum) {
maxNum = arr.length;
maxPaths = [arr];
}
if (arr.length === maxNum) {
maxPaths.push(arr)
}
}
};
const searchWords = (word, res) => {
const cs = getCandidates(lookup.get(endsWith(word)) || [], res);
return cs.length ? cs.map(e => searchWords(e, [...res, e])) : res;
};
names.forEach(word => {
const res = searchWords(word, [word]);
parseResult(res);
});
const t1 = process.hrtime(t0);
console.info('Execution time (hr): %ds %dms', t1[0], t1[1] / 1000000);
console.log('Max Path:', maxNum);
console.log('Matching Paths:', maxPaths.length);
console.log('Example Path:', maxPaths[0]);
};
const pokimon = ["audino", "bagon", "baltoy", "banette",
"bidoof", "braviary", "bronzor", "carracosta", "charmeleon",
"cresselia", "croagunk", "darmanitan", "deino", "emboar",
"emolga", "exeggcute", "gabite", "girafarig", "gulpin",
"haxorus", "heatmor", "heatran", "ivysaur", "jellicent",
"jumpluff", "kangaskhan", "kricketune", "landorus", "ledyba",
"loudred", "lumineon", "lunatone", "machamp", "magnezone",
"mamoswine", "nosepass", "petilil", "pidgeotto", "pikachu",
"pinsir", "poliwrath", "poochyena", "porygon2", "porygonz",
"registeel", "relicanth", "remoraid", "rufflet", "sableye",
"scolipede", "scrafty", "seaking", "sealeo", "silcoon",
"simisear", "snivy", "snorlax", "spoink", "starly", "tirtouga",
"trapinch", "treecko", "tyrogue", "vigoroth", "vulpix",
"wailord", "wartortle", "whismur", "wingull", "yamask"];
findPaths(pokimon);