编辑代码

const { isNumberObject } = require("util/types");

// 设置标准输入接口
const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void (async function () {
  const val = (await readline()).split(" ");
  let res = 0;
  const numStack = [];
  for (let i = 0; i < val.length; i++) {
    const c = val[i];

    if (!isNaN(Number(c))) {
      numStack.push(Number(c));
    } else if (c == "C") {
      numStack.pop();
    } else if (c == "D") {
      const num = numStack[numStack.length - 1];
      numStack.push(num * 2);
    } else if (c == "+") {
      const num1 = numStack[numStack.length - 1];
      const num2 = numStack[numStack.length - 2];
      numStack.push(num1 + num2);
    }
  }
  for (let i = 0; i < numStack.length; i++) {
    res += numStack[i];
  }
  console.log(res);
})();