최소 신장 트리

<canvas id="stage"></canvas><div class="controls"><button id="restart" type="button">처음부터</button><button id="step" type="button">한 단계</button><label>속도 <input id="speed" type="range" min="1" max="5" value="3"></label></div>

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const title = "최소 신장 트리 · 간선 선택";
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