题解 | 字符个数统计
字符个数统计
https://www.nowcoder.com/practice/eb94f6a5b2ba49c6ac72d40b5ce95f50
使用哈希，没有就加入哈希表，有就不用操作，最后输出哈希表长度
const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;
void async function () {
// Write your code here
const line = await readline()
const hashMap = new Map()
for(const char of line){
if(!hashMap.has(char)) hashMap.set(char,1)
}
console.log(hashMap.size)
}()
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