题解 | #自守数#

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void async function () {
    
    while(line = await readline()){
        let num = Number(line);
        let count = 0;
        for(let i=0; i<=num;i++){
            if(isSelf(i)){
                count ++;
            }
        }
        console.log(count);
    }
    //判断是否是自守数的方法
    function isSelf(n){
        let s = n.toString();
        let ss = (n*n).toString();
        if(ss.endsWith(s)) return true;
        return false;
    }
}()