Codeforces: Export All Problems to PDF

Export all Codeforces contest problems to a printable PDF, styled like CPC contests.

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

Bạn sẽ cần cài đặt một tiện ích mở rộng như Tampermonkey hoặc Violentmonkey để cài đặt kịch bản này.

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.

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

(Tôi đã có Trình quản lý tập lệnh người dùng, hãy cài đặt nó!)

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         Codeforces: Export All Problems to PDF
// @namespace    https://github.com/AnonMiraj
// @author       ezzeldin
// @license      GPL3
// @description  Export all Codeforces contest problems to a printable PDF, styled like CPC contests.
// @match        https://codeforces.com/group/*/contest/*
// @match        https://codeforces.com/gym/*
// @match        https://codeforces.com/contest/*
// @grant        none
// @esversion 11
// @version 1.0
// ==/UserScript==

(function () {
    'use strict';

    if (!document.querySelector('table.datatable') && !document.querySelector('table.problems')) return;

    const container = document.querySelector('div[style*="text-align: right"] a[href*="/problems"]')?.parentElement;
    if (!container) return;
    const originalHTML = document.body.innerHTML;
    const pdfLink = document.createElement('a');
    pdfLink.textContent = '💾 Save All as PDF';
    pdfLink.href = '#';
    pdfLink.style.marginLeft = '15px';
    pdfLink.style.color = '#0066cc';
    pdfLink.style.textDecoration = 'none';
    pdfLink.style.cursor = 'pointer';
    container.appendChild(pdfLink);

    pdfLink.addEventListener('click', async (e) => {
        e.preventDefault();
        await exportPDF(pdfLink);
    });

    async function exportPDF(link) {
        const originalText = link.textContent;
        link.style.pointerEvents = 'none';
        link.textContent = 'Fetching…';

        const selectors = [
            'table.datatable tr td.id a',
            'table.datatable tr td.index a',
            'table.problems tr td.id a',
            'table.problems tr td.index a',
            'table.datatable tr a[href*="/problem/"]',
            'table.problems tr a[href*="/problem/"]'
        ];

        const anchors = Array.from(document.querySelectorAll(selectors.join(',')));
        const seen = new Set(), links = [];
        anchors.forEach(a => {
            if (!seen.has(a.href)) {
                seen.add(a.href);
                links.push(a.href);
            }
        });

        if (!links.length) return alert('No problem links found!');

        const problemsHTML = await Promise.all(
            links.map(url => fetchProblem(url))
        );

        document.body.innerHTML = problemsHTML
            .map((html, i) => html || `<div><h2>Problem ${links[i].split('/').pop()} failed to load.</h2></div>`);

        document.querySelectorAll('.test-example-line-even, .test-example-line-odd').forEach(el => {
            el.classList.remove('test-example-line-even', 'test-example-line-odd');
        });

        document.querySelectorAll('.problem-statement').forEach((prob, i, arr) => {
            const inputs = prob.querySelectorAll('.input');
            const outputs = prob.querySelectorAll('.output');
            if (inputs.length && outputs.length) {
                const table = document.createElement('table');
                table.className = 'samples-table';
                table.style.width = '100%';
                table.style.borderCollapse = 'collapse';
                table.style.marginBottom = '20px';

                const header = table.insertRow();
                ['Standard Input', 'Standard Output'].forEach(text => {
                    const th = document.createElement('th');
                    th.textContent = text;
                    th.style.border = '1px solid black';
                    th.style.padding = '8px';
                    th.style.textAlign = 'center';
                    th.style.width = '50%';
                    header.appendChild(th);
                });

                for (let j = 0; j < Math.min(inputs.length, outputs.length); j++) {
                    const row = table.insertRow();
                    [inputs[j], outputs[j]].forEach(el => {
                        const cell = row.insertCell();
                        cell.style.border = '1px solid black';
                        cell.style.padding = '8px';
                        cell.style.verticalAlign = 'top';
                        cell.appendChild(el);
                    });
                }

                const sample = prob.querySelector('.sample-tests') || prob.querySelector('.sample-test') || prob;
                sample?.parentNode?.insertBefore(table, sample.nextSibling);
                prob.querySelector('.sample-tests')?.remove();
                prob.querySelector('.sample-test')?.remove();
            }

            if (i < arr.length - 1) {
                const pageBreak = document.createElement('div');
                pageBreak.style.pageBreakBefore = 'always';
                prob.parentNode.insertBefore(pageBreak, prob.nextSibling);
            }
        });

        const style = document.createElement('style');
        style.textContent = `
            .samples-table th, .samples-table td {
                border: 1px solid black;
                padding: 8px;
                vertical-align: top;
                text-align: left;
            }
            .samples-table pre {
                white-space: pre-wrap;
                word-wrap: break-word;
                font-size: 12px;
                margin: 0;
            }
            @media print {
                .samples-table th, .samples-table td {
                    border: 1px solid black;
                    padding: 8px;
                }
            }
        `;
        document.head.appendChild(style);

        ['#MathJax_Message', '.status-bar', '#status', '.print-hide']
            .forEach(sel => document.querySelectorAll(sel).forEach(el => el.style.display = 'none'));

        const finalize = () => setTimeout(() => {
            document.getElementById('MathJax_Message')?.style.setProperty('display', 'none', 'important');
            window.print();

            setTimeout(() => {
                document.body.innerHTML = originalHTML;
                link.style.pointerEvents = '';
                link.textContent = originalText;
            }, 500);
        }, 500);

        if (window.MathJax) {
            try {
                if (MathJax.typesetPromise) {
                    await MathJax.typesetPromise([document.body]);
                    finalize();
                } else if (MathJax.Hub?.Queue) {
                    MathJax.Hub.Queue(["Typeset", MathJax.Hub, document.body], finalize);
                } else finalize();
            } catch (e) {
                finalize();
            }
        } else finalize();

        link.style.pointerEvents = '';
        link.textContent = originalText;
    }

    async function fetchProblem(url, retries = 2) {
        try {
            const res = await fetch(url);
            const txt = await res.text();
            const doc = new DOMParser().parseFromString(txt, 'text/html');
            const prob = doc.querySelector('.problem-statement');
            if (!prob) throw new Error('Missing problem-statement');

            prob.querySelectorAll('.input-output-copier').forEach(el => el.remove());

            const header = doc.querySelector('.header');
            let title = 'Unknown Problem';
            let inputFile = 'standard input';
            let outputFile = 'standard output';
            let timeLimit = 'N/A';
            let memoryLimit = 'N/A';

            if (header) {
                title = header.querySelector('.title')?.textContent.trim() || title;
                inputFile = header.querySelector('.input-file')?.textContent.replace('input', '').trim() || inputFile;
                outputFile = header.querySelector('.output-file')?.textContent.replace('output', '').trim() || outputFile;
                timeLimit = header.querySelector('.time-limit')?.textContent.replace('time limit per test', '').trim() || timeLimit;
                memoryLimit = header.querySelector('.memory-limit')?.textContent.replace('memory limit per test', '').trim() || memoryLimit;
                header.remove();
            }

            const h2 = document.createElement('h2');
            h2.textContent = title;
            h2.style.marginBottom = '0.2em';
            h2.style.textAlign = 'left';
            prob.insertBefore(h2, prob.firstChild);

            const metaDiv = document.createElement('div');
            metaDiv.className = 'problem-metadata';
            metaDiv.style.marginBottom = '1em';
metaDiv.innerHTML = `
    <pre style="font-family: monospace; margin-left: 20px; font-size: 14px;">
Input file:\t${inputFile}
Output file:\t${outputFile}
Time limit:\t${timeLimit}
Memory limit:\t${memoryLimit}
    </pre>
`;


            prob.insertBefore(metaDiv, prob.firstChild.nextSibling);

            prob.querySelectorAll('.input .title, .output .title').forEach(el => el.remove());
            return prob.outerHTML;

        } catch (err) {
            if (retries > 0) {
                await new Promise(r => setTimeout(r, 400));
                return fetchProblem(url, retries - 1);
            }
            return null;
        }
    }
})();