181913

function solution(my_string, queries) {
  let str = my_string.split("");
  queries.forEach(([start, end]) => {
    const changeStr = str.slice(start, end + 1);
    str.splice(start, changeStr.length, ...changeStr.reverse());
  });
  return str.join("");
}

function solution(my_string, queries) {
  const str = [...my_string];
  queries.forEach(([s, e]) => {
    while (s < e) {
      [str[s], str[e]] = [str[e], str[s]];
      s++;
      e--;
    }
  });
  return str.join("");
}