Longest Common Prefix

longest-common-prefix.ts

function longestCommonPrefix(words: string[]): string {
  if (words.length === 0) {
    return "";
  }

  const prefixes = [];
  const firstWord = words[0] as string;

  for (let j = 0; j < firstWord.length; j++) {
    const prefix = firstWord.slice(0, j);
    const allOthersWordsStartsWithPrefix = words.slice(1).every((word) => word.startsWith(prefix));

    if (allOthersWordsStartsWithPrefix) {
      prefixes.push(prefix);
    }
  }

  const longestPrefix = prefixes.at(-1) as string;

  return longestPrefix;
}