3. Post Office (RegExp)

function solve(input) {
  let string = input.shift();
  let [first, second, third] = string.split("|");
  let firstPattern = /([$\*#%&])([A-Z]+)\1/gm;
  let secondPattern = /([0-9]{2}\:[0-9]{2})+/gm;
  let firstGroup = Array.from(first.matchAll(firstPattern))[0][2];
  let secondGroup = Array.from(second.match(secondPattern));
  let ascis = [];
  let lengths = [];
  secondGroup.forEach(pair => {
    let [asciCode, length] = pair.split(":");
    ascis.push(Number(asciCode));
    lengths.push(Number(length));
  });

  let thirdGroup = third.split(" ");

  for (const letter of firstGroup) {
    thirdGroup.forEach(word => {
      let index = ascis.indexOf(letter.charCodeAt());
      if (word[0] === letter && word.length === lengths[index] + 1) {
        console.log(word);
      }
    });
  }
}