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AtCoder Graph Visualizer

入力例のグラフを推定して、オプション付きで頂点と辺をSVG描画

Från och med 2025-08-17. Se den senaste versionen.

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

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.

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

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

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         AtCoder Graph Visualizer
// @namespace    https://example.com/
// @version      1.2.1
// @description  入力例のグラフを推定して、オプション付きで頂点と辺をSVG描画
// @match        https://atcoder.jp/contests/*/tasks/*
// @run-at       document-idle
// @grant        none
// @license      MIT
// ==/UserScript==

(function () {
  'use strict';

  function el(tag, attrs = {}, children = []) {
    const e = document.createElement(tag);
    Object.entries(attrs).forEach(([k, v]) => {
      if (k === 'style' && typeof v === 'object') Object.assign(e.style, v);
      else if (k.startsWith('on') && typeof v === 'function') e.addEventListener(k.slice(2), v);
      else e.setAttribute(k, v);
    });
    (Array.isArray(children) ? children : [children]).forEach(c => {
      if (c == null) return;
      if (typeof c === 'string') e.appendChild(document.createTextNode(c));
      else e.appendChild(c);
    });
    return e;
  }

  function parseInts(line) {
    return (line.match(/-?\d+/g) || []).map(s => Number(s));
  }

  function parseGraphFromSample(sampleText, forceTree = false) {
    const lines = sampleText.replace(/\t/g, ' ').replace(/\r/g, '').split('\n')
      .map(s => s.trim()).filter(s => s.length > 0);
    const rows = lines.map(parseInts).filter(a => a.length > 0);
    if (rows.length === 0) return null;

    let N = null, M = null, edgeStartIdx = null;

    if (forceTree) {
      N = rows[0][0];
      M = N - 1;
      edgeStartIdx = 1;
    } else if (rows[0].length >= 2) {
      N = rows[0][0];
      M = rows[0][1];
      edgeStartIdx = 1;
    } else if (rows[0].length === 1) {
      if (rows.length >= 2 && rows[1].length === 1) {
        N = rows[0][0];
        M = rows[1][0];
        edgeStartIdx = 2;
      } else {
        N = rows[0][0];
        const edgeCandidates = rows.slice(1).filter(a => a.length >= 2);
        if (edgeCandidates.length === N - 1 && N >= 2) {
          M = N - 1;
          edgeStartIdx = 1;
        } else {
          return null;
        }
      }
    } else {
      return null;
    }

    const edges = [];
    let maxV = N || 0;
    for (let i = 0; i < M; i++) {
      const idx = edgeStartIdx + i;
      if (idx >= rows.length) break;
      const a = rows[idx];
      if (a.length < 2) break;
      const u = a[0], v = a[1];
      const w = a.length >= 3 ? a[2] : null;
      edges.push({ u, v, w });
      maxV = Math.max(maxV, u, v);
    }

    if (edges.length === 0) return null;
    const V = Math.max(N || 0, maxV);
    if (!(V >= 1) || !(edges.length >= 1)) return null;
    return { N: V, M: edges.length, edges };
  }

  function renderGraphSVG(graph, opts, width = 420, height = 420) {
    const { N, edges } = graph;
    const { directed, weighted } = opts;
    const margin = 24;
    const cx = width / 2, cy = height / 2;
    const R = Math.min(width, height) / 2 - margin;

    const pos = new Map();
    for (let i = 1; i <= N; i++) {
      const theta = (2 * Math.PI * (i - 1)) / N - Math.PI / 2;
      pos.set(i, { x: cx + R * Math.cos(theta), y: cy + R * Math.sin(theta) });
    }

    const svgNS = 'http://www.w3.org/2000/svg';
    const svg = document.createElementNS(svgNS, 'svg');
    svg.setAttribute('width', String(width));
    svg.setAttribute('height', String(height));
    svg.style.display = 'block';
    svg.style.border = '1px solid #ddd';
    svg.style.borderRadius = '12px';
    svg.style.marginTop = '8px';
    svg.style.background = 'white';

    if (directed) {
      const defs = document.createElementNS(svgNS, 'defs');
      const marker = document.createElementNS(svgNS, 'marker');
      marker.setAttribute('id', 'arrowhead');
      marker.setAttribute('markerWidth', '10');
      marker.setAttribute('markerHeight', '7');
      marker.setAttribute('refX', '10');
      marker.setAttribute('refY', '3.5');
      marker.setAttribute('orient', 'auto');
      const path = document.createElementNS(svgNS, 'path');
      path.setAttribute('d', 'M0,0 L10,3.5 L0,7 Z');
      path.setAttribute('fill', '#555');
      marker.appendChild(path);
      defs.appendChild(marker);
      svg.appendChild(defs);
    }

    edges.forEach(({ u, v, w }) => {
      const pu = pos.get(u), pv = pos.get(v);
      if (!pu || !pv) return;
      const line = document.createElementNS(svgNS, 'line');
      line.setAttribute('x1', pu.x.toFixed(2));
      line.setAttribute('y1', pu.y.toFixed(2));
      line.setAttribute('x2', pv.x.toFixed(2));
      line.setAttribute('y2', pv.y.toFixed(2));
      line.setAttribute('stroke', '#888');
      line.setAttribute('stroke-width', '1.5');
      if (directed) line.setAttribute('marker-end', 'url(#arrowhead)');
      svg.appendChild(line);

      if (weighted && w != null) {
        const tx = (pu.x + pv.x) / 2, ty = (pu.y + pv.y) / 2;
        const label = document.createElementNS(svgNS, 'text');
        label.setAttribute('x', tx.toFixed(2));
        label.setAttribute('y', ty.toFixed(2));
        label.setAttribute('font-size', '11');
        label.setAttribute('text-anchor', 'middle');
        label.setAttribute('dominant-baseline', 'central');
        label.setAttribute('fill', '#444');
        label.textContent = String(w);
        svg.appendChild(label);
      }
    });

    for (let i = 1; i <= N; i++) {
      const { x, y } = pos.get(i);
      const g = document.createElementNS(svgNS, 'g');
      const circle = document.createElementNS(svgNS, 'circle');
      circle.setAttribute('cx', x.toFixed(2));
      circle.setAttribute('cy', y.toFixed(2));
      circle.setAttribute('r', '12');
      circle.setAttribute('fill', '#f5f5f5');
      circle.setAttribute('stroke', '#333');
      circle.setAttribute('stroke-width', '1.5');
      g.appendChild(circle);

      const text = document.createElementNS(svgNS, 'text');
      text.setAttribute('x', x.toFixed(2));
      text.setAttribute('y', y.toFixed(2));
      text.setAttribute('font-size', '12');
      text.setAttribute('font-weight', '600');
      text.setAttribute('text-anchor', 'middle');
      text.setAttribute('dominant-baseline', 'central');
      text.textContent = String(i);
      g.appendChild(text);

      svg.appendChild(g);
    }

    return svg;
  }

  function findSamplePreBlocks() {
    const pres = [];
    const headings = Array.from(document.querySelectorAll('h3, h4'));
    headings.forEach(h => {
      const txt = (h.textContent || '').trim();
      if (/入力例|Sample Input/i.test(txt)) {
        let el = h.nextElementSibling;
        while (el && el.tagName.toLowerCase() !== 'pre') el = el.nextElementSibling;
        if (el && el.tagName.toLowerCase() === 'pre') pres.push(el);
      }
    });
    return pres;
  }

  function alreadyRendered(pre) {
    return pre.nextElementSibling && pre.nextElementSibling.classList?.contains('ac-graph-viz-container');
  }

  function tryRenderForPre(pre) {
    if (!pre || alreadyRendered(pre)) return;
    const text = pre.textContent || '';

    let directed = false;
    let forceTree = false;
    let weighted = false;
    const svgArea = el('div', {});

    function redraw() {
      svgArea.innerHTML = '';
      const graph = parseGraphFromSample(text, forceTree);
      if (graph) {
        svgArea.appendChild(renderGraphSVG(graph, { directed, weighted }));
      } else {
        svgArea.appendChild(el('div', { style: { fontSize: '12px', color: '#a00' } },
          'グラフ入力を検出できなかったため描画をスキップした。'));
      }
    }

    const directedBox = el('input', { type: 'checkbox', onchange: e => { directed = e.target.checked; redraw(); } });
    const treeBox = el('input', { type: 'checkbox', onchange: e => { forceTree = e.target.checked; redraw(); } });
    const weightedBox = el('input', { type: 'checkbox', onchange: e => { weighted = e.target.checked; redraw(); } });

    const header = el('div', {
      style: {
        fontSize: '12px',
        color: '#555',
        marginBottom: '6px',
        display: 'flex',
        gap: '8px',
        alignItems: 'center',
        flexWrap: 'wrap',
      }
    }, [
      el('span', {}, '🗺️ グラフ可視化(推定)'),
      el('label', {}, [directedBox, ' 有向グラフ']),
      el('label', {}, [treeBox, ' 木としてみる']),
      el('label', {}, [weightedBox, ' 重み付きグラフ'])
    ]);

    const container = el('div', {
      class: 'ac-graph-viz-container',
      style: { marginTop: '8px', marginBottom: '20px' }
    }, [header, svgArea]);

    pre.parentNode.insertBefore(container, pre.nextSibling);
    redraw();
  }

  function main() {
    const pres = findSamplePreBlocks();
    pres.forEach(tryRenderForPre);
  }

  main();
  const mo = new MutationObserver(() => main());
  mo.observe(document.documentElement, { childList: true, subtree: true });
})();