split.js

const fs = require('fs');
const words = [];

for (const line of fs.readFileSync(process.argv[2], 'utf8').trim().split('\n')) {
  const word = line.trim();
  words[word.length - 2] = words[word.length - 2] || [];
  words[word.length - 2].push(word);
}

for (let n = 5; n <= 5; n++) {
  const bucket = words[n - 2];
  const shapes = {};
  //console.error(i);
  //const pairs = consecutive(bucket);
  const result = findWordsWithTwoLetterDifference(bucket);
  for (const [mask, all] of result.entries()) {
    const all = result.get(mask);
    if (all.length <= 1) continue;

    const index = mask.indexOf('*');

   for (let i = 0; i < all.length; i++) {
    for (let j = i + 1; j < all.length; j++) {
      const key = `${'_'.repeat(index)}(${all[i].substring(index, index + 2)}|${all[j].substring(index, index + 2)})${'_'.repeat(n - index - 2)}`;
      shapes[key] = shapes[key] || [];
      shapes[key].push([all[i], all[j]]);
    }
  }


    //console.log(mask, all.join(' '));
  }

  const sorted = Object.keys(shapes);
  sorted.sort((a, b) => shapes[b].length - shapes[a].length);

  for (const key of sorted) {
    console.log(key.toUpperCase(), shapes[key].map(pair => pair.join('/')).join(' '));
  }
}

function consecutive(words) {
  if (words.length === 0) {
    return {};
  }

  const wordLength = words[0].length;
  const result = {};

  for (let i = 0; i < words.length; i++) {
    for (let j = i + 1; j < words.length; j++) {
      for (let k = 0; k < wordLength - 1; k++) {
        if (words[i].substring(k, k + 2) === words[j].substring(k, k + 2)) {
          const key = `${'_'.repeat(k)}${words[i].substring(k, k + 2)}${'_'.repeat(words[i].length - k - 2)}`;
          result[key] = result[key] || new Set();
          result[key].add(words[i])
          result[key].add(words[j]);
          break;
        }
      }
    }
  }

  return result;
}

function findWordsWithTwoLetterDifference(words) {
  const wordLength = words[0].length;
  const maskedWordsMap = new Map();

  for (const word of words) {
    if (word.endsWith('ed') || word.endsWith('s') || word.endsWith('er') || word.endsWith('ing')) continue;
    for (let i = 0; i < wordLength - 1; i++) {
      const maskedWord = word.substring(0, i) + "**" + word.substring(i + 2);
      if (!maskedWordsMap.has(maskedWord)) {
        maskedWordsMap.set(maskedWord, []);
      }
      maskedWordsMap.get(maskedWord).push(word);
    }
  }

  return  maskedWordsMap;
}