题解 | #字符个数统计#
字符个数统计
http://www.nowcoder.com/practice/eb94f6a5b2ba49c6ac72d40b5ce95f50
const readline = require('readline') var rl = readline.createInterface({ input:process.stdin, output:process.stdout }) var str = '' rl.on('line',(line)=>{ str = line }) rl.on('close',()=>{ var arr = str.split('') var s = new Set(arr.reverse()) var arr2 = [...s] console.log(arr2.length) })