题解 | #找出字符串中第一个只出现一次的字符#

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
   let str = await readline()
   let map = new Map()
   let keyWords = []
   for(let i=0; i<str.length; i++) {
      let char = str[i]
       map.has(char) ? map.set(char,map.get(char)+1) : map.set(char,1)
    }
    for(const [key, value] of map) {
        if(value == 1) {
            keyWords.push(key)
        }
    }

    if(keyWords.length == 0) {
         console.log(-1)
   }else {
   for(let j=0; j<str.length; j++) {
        if(keyWords.includes(str[j])) {
          console.log(str[j])
          break
        }  
    }
   }
    
}()