Morain

``` JavaScript //倒序循环可避免 const arr = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 0, 0, 0, 1, 9, 9, 9, 0, 0, 0, 0,...

> > ```js > > //倒序循环可避免 > > const arr = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 0, 0, 0, 1, 9, 9,...

``` const deal = (source) => { const arr = source.split(',') const len = arr.length let str = '' let arr2 = [] for (let i = 0; i <...