编辑代码

// 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 arr = (await readline()).split(",").map(Number);
  let leftSum = 0,
    rightSum = arr.reduce((a, b) => a + b, 0);
  let i = 0;
  let hasVal = false;
  while (i < arr.length) {
    if (i > 0) leftSum += arr[i - 1];
    rightSum -= arr[i];
    if (leftSum === rightSum) {
      console.log(i);
      hasVal = true;
      break;
    }
    i++;
  }
  if (!hasVal) console.log(-1);
})();