题目，根据传入的正整数，画一颗树

![Uploading Paste_Image_548301.png . . .]

我的解答

function towerBuilder(nFloors) {
  var box = [];
  nFloors = nFloors*2 - 1;
  while (nFloors > 0) {
      box.push(nFloors);
      nFloors = nFloors - 2;
  }
  var box2 = [];
  box.forEach(function(item, index, array) {
      var box3 = [];
      for (i=0; i< index; i++) {box3.push(' ')};
      for (j=0; j< item; j++) {box3.push('*')};
      for (k=0; k< index; k++) {box3.push(' ')};
      var level = box3.join('');
      box2.push(level);
  });
  
  return box2.reverse();
}

别人的解答

function towerBuilder(n) {
  return Array.from({length: n}, function(v, k) {
    const spaces = ' '.repeat(n - k - 1);
    return spaces + '*'.repeat(k + k + 1) + spaces;
  });
}

我的感想

• “别人的解答”表示不是很懂
• JS居然不能像python一样 2* 'a' = 'aa'，好麻烦，哈哈哈哈