Function isCommonPrefix

daily/answers/14.longest-common-prefix.js:7–14

(strs, middle)

 */

function isCommonPrefix(strs, middle) {
  const prefix = strs[0].substring(0, middle);
  for (let i = 1; i < strs.length; i++) {
    if (!strs[i].startsWith(prefix)) return false;
  }

  return true;
}
/**
 * @param {string[]} strs
 * @return {string}