题解 | #合法IP#

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
    while ((line = await readline())) {
        let tokens = line.split(".");
        if (
            tokens.length !== 4 ||
            !tokens[0] ||
            !tokens[1] ||
            !tokens[2] ||
            !tokens[3]
        ) {
            console.log("NO");
        } else {
            let i = 0;
            while (i < 4) {
                let str = tokens[i];
                let number = parseInt(tokens[i]);
                let numberStr = number.toString();
                if (
                    numberStr.length < str.length ||
                    number < 0 ||
                    number > 255
                ) {
                    console.log("NO");
                    break;
                }
                i++;
            }
            if (i === 4) console.log("YES");
        }
    }
})();