题解 | #查找两个字符串a,b中的最长公共子串#

let s1 = readline();
let s2 = readline();
let left = 0;
right = 0;
let maxLen = 0;
let res = "";
let short = s1.length >= s2.length ? s2 : s1;
let long = s1.length >= s2.length ? s1 : s2;
while (right < short.length) {
  let subStr = short.substring(left, right + 1);
  while (!long.includes(subStr)) {
    left++;
    subStr = short.substring(left, right + 1);
  }
  if (right - left + 1 > maxLen) {
    maxLen = right - left + 1;
    res = subStr;
  }
  right++;
}
console.log(res);