题解 | #字符个数统计#
字符个数统计
https://www.nowcoder.com/practice/eb94f6a5b2ba49c6ac72d40b5ce95f50
可以用set方法直接去重解题 一行代码解决 也可以用哈希表思路解题 完整代码如下：
const readline = require("readline");
const rl = readline.createInterface({
input: process.stdin,
output: process.stdout,
});
rl.on("line", function (line) {
let arr = line.toLowerCase().split('')
let res = [];
let object = {};
for (let i = 0; i < arr.length; i++) {
if (! object[arr[i]]) {
res.push(arr[i]);
object[arr[i]] = true
}
}
console.log(res.length);
});
