export function lcs(wordX, wordY, m = wordX.length, n = wordY.length) {
  if (m === 0 || n === 0) {
    return 0;
  }
  if (wordX[m - 1] === wordY[n - 1]) {
    return 1 + lcs(wordX, wordY, m - 1, n - 1);
  }
  const a = lcs(wordX, wordY, m, n - 1);
  const b = lcs(wordX, wordY, m - 1, n);
  return a > b ? a : b;
}