题解 | #数据分类处理#

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void (async function () {
  // Write your code here
  let arr = [];
  while ((line = await readline())) {
    arr.push(line);

    if (arr.length == 2) {
      let IArr = arr[0].split(" ");
      let RArr = arr[1].split(" ");

      IArr.shift();
      RArr.shift();
      RArr = [...new Set(RArr.sort((a, b) => a - b))];
      let log = [];

      RArr.forEach((item) => {
        let itemArr = [];
        for (let i = 0; i < IArr.length; i++)
          if (IArr[i].includes(item))
            itemArr.push(i, IArr[i]);
        if (itemArr.length !== 0)
          log.push(item, itemArr.length / 2, ...itemArr);
      });
      log.unshift(log.length);

      console.log(log.join(" "));
    }
  }
})();