题解 | #找出字符串中第一个只出现一次的字符#

const readline = require("readline");
const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
});
let found = false; // 记录是否找到符合条件的字符串
rl.on("line", (line) => {
    

    for (let s of line) {
        const arr = line.split(s);
        if (arr.length == 2) {
            console.log(s);
            found = true;
            break;
        }
    }

    if (!found) {
        console.log(-1);
    }
});