['1a', '3b', '1c', '2a', '7b', '2a']这样一个由数字和字母构成的数组，求出现最多次字母的前系数和

function sortting(obj) {let result = []var count = 0; //用来创建新数组var max = 0; //找出系数最大值for (var item in obj) {var temp = obj[item].substring(obj[item].length - 1, obj[item].length);if (result[count] != undefined) {var curentcount = count;if (result[count].name == temp) {result[count].value = +Number(obj[item].substring(0, obj[item].length - 1))} else {var book = falsewhile (count--) {if (result[count].name == temp) {result[count].value += Number(obj[item].substring(0, obj[item].length - 1))book = true}if (result[count].value > max) {max = result[count].value}}count = curentcount;if (book == false) {count++;result[count] = {name: obj[item].substring(obj[item].length - 1, obj[item].length),value: Number(obj[item].substring(0, obj[item].length - 1))};if (result[count].value > max) {max = result[count].value}}}} else {result[count] = {name: obj[item].substring(obj[item].length - 1, obj[item].length),value: Number(obj[item].substring(0, obj[item].length - 1))};if (result[count].value > max) {max = result[count].value}}}console.log(result,max)}let result = ['1a', '3b', '1c', '2a', '7b', '2a','6d','10a','20b']sortting(result)

第一种方法估计就是另开数组把系数作为value，字母作为key，在另外操作，这样不是最优解，虽然我不知道我的是不是，但是效率是n，应该会好点