//includes indexOf splice配合使用,简单易懂 function maxLength( arr ) { let tmp = []; let res = 0; for(let i = 0; i < arr.length; i++){ if(!tmp.includes(arr[i])){ tmp.push(arr[i]); if(tmp.length > res){ res = tmp.length; } } else{ tmp.splice(0,tmp.indexOf(arr[i]) + 1); tmp.push(arr[i]); } } return res } module.exports = { maxLength : maxLength };