function wordBreak(words: string[], sentence: string): string[] | null {
  if (words.join() === sentence) return words;
  const arr: [number, string][] = [];
  for (const word of words) {
    const wordIndex = sentence.indexOf(word);
    if (wordIndex === -1) return null
    if (arr.some(([i]) => i === wordIndex)) return null
    arr.push([wordIndex, word]);
  }

  const result = arr.toSorted(([a], [b]) => a - b).map(([, s]) => s);
  return result;
}

// No modificar: necesario para evaluar el resultado.
export { wordBreak };