AtCoderLeftShiftOverflowWarning

Warn you when you write `1 << x` on AtCoder.

Du musst eine Erweiterung wie Tampermonkey, Greasemonkey oder Violentmonkey installieren, um dieses Skript zu installieren.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

Sie müssten eine Skript Manager Erweiterung installieren damit sie dieses Skript installieren können

(Ich habe schon ein Skript Manager, Lass mich es installieren!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name         AtCoderLeftShiftOverflowWarning
// @namespace    https://github.com/AwashAmityOak
// @version      0.1.0
// @description  Warn you when you write `1 << x` on AtCoder.
// @author       AwashAmityOak
// @license      MIT
// @match        https://atcoder.jp/contests/*/tasks/*
// @match        https://atcoder.jp/contests/*/submit*
// @grant        unsafeWindow
// @copyright    2025 AwashAmityOak (https://github.com/AwashAmityOak)
// ==/UserScript==

(function() {
    'use strict';

    const $ = unsafeWindow.$;

    ace.edit("editor").addEventListener("change", () => {
        const button = $("#submit");

        const lang = $("#select-lang select[name='data.LanguageId']");
        if (lang.find(":selected").text().indexOf("C++") == -1) return;

        const code = ace.edit("editor").getValue();

        if (/(?<!<<\s*)(?<![a-zA-Z_])\d+\s*<</.test(code)) {
            let br = $("<br>");
            let span = $("<span>⚠️左シフトオーバーフロー</span>");
            br.addClass("AtCoderLeftShiftOverflowNotifier");
            span.addClass("AtCoderLeftShiftOverflowNotifier");

            if (!$("br.AtCoderLeftShiftOverflowNotifier").length) button.append(br);
            if (!$("span.AtCoderLeftShiftOverflowNotifier").length) button.append(span);

            button.css("backgroundColor", "#cc3333");
            button.css("borderColor", "#cc3333");
        } else {
            $(".AtCoderLeftShiftOverflowNotifier").remove();
            button.css("backgroundColor", "");
            button.css("borderColor", "");
        }
    });
})();