摒弃纯计算模式,利用循环创建出行数个数组

const num = parseInt(readline());
let start = 1;
let arr = new Array(num).fill(0).map((v) => new Array());
for (let i = 0; i < num; i++) {
  for (let j = i; j >= 0; j--) {
    arr[j][i] = start++;
  }
}
let res = arr
  .map((item) => {
    return item.join(" ").trim();
  })
  .forEach((item) => {
    console.log(item);
  });