题解 | #截取字符串#

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
    var index = 0;
    var str;
    while(line = await readline()){
        switch(index){
            case 0: str=line; ++index; break;
            case 1: console.log(str.slice(0,parseInt(line)));break;
            default: break;
        }
    }
}()