//排列后的结果:123/132/213/231/312/321const arr =[1,2,3]let res =[]functionpai(data, s =[]){if(s.length === data.length){
res.push(s)}for(let i =0; i < data.length; i++){const e = data[i];const copy = data.slice()//截取数组传递下去
copy.splice(i,1)pai(copy, s.concat(e))}}pai(arr)