export function intercalateChars(first: string, second: string): string {
  let res: string = '';
  let i: number = 0;
  const indexFinal: number = first.length + second.length;
  while (i < indexFinal) {
    if (first.length > i) res += first[i];
    if (second.length > i) res += second[i];
    i++;
  }
  return res;
}