二面的算法题可以直接用Map function main(arr) { let map = new Map(),ans = []; arr.forEach((value) => { map.has(value) ? map.set(value,(map.get(value) + 1)) : map.set(value,1); }); map.forEach((value,key) => { ans.push(`${key}`); ans.push(`${value}`); }); return ans; } const arrest = ["a","a","b","b","c"]; console.log(main(arrest));