Question

通过阅读Wiki Prims示例 https://en.wikipedia.org/wiki/Prim%27s_algorithm

指向3c-

在将v连接到其他顶点w的边缘vw上环绕。对于每个这样的边，如果w仍然属于Q，并且vw的权重小于C [w]，则执行以下步骤：

将C [w]设置为边vw的代价设置E [w]指向边缘vw。

因此，如果vw

如果我让它运行，我会得到这个。

这是我到目前为止所拥有的...

<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>MST - Prims Algorithm Solution</title> <style> body { padding: 0px; margin: 0px; } canvas { background-image: url('./gfx/map25.png'); width: 2000px; height: 1100px; } </style> </head> <body> <canvas id="map"></canvas> <script> class Place { constructor(name, x, y, id) { this.id = id; this.name = name; this.x = x; this.y = y; this.edges = []; this.C = 99999; // Wiki - the cheapest cost of a connection to v this.E = null; // Wiki - the edge providing that cheapest connection } } class Edge { constructor(node1, node2, id) { this.id = id; this.node1 = node1; this.node2 = node2; } get distance() { let dx = this.node1.x - this.node2.x; let dy = this.node1.y - this.node2.y; return Math.sqrt( dx*dx + dy*dy ); } } let edges = []; let edgeData = 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1100; // The forest (F) and visited list (Q) let F = {places: [], edges: []}; let Q = []; document.addEventListener("DOMContentLoaded", ()=> { // Create the nodes / place instances placeData.forEach((place)=>{ places.push(new Place(place.name, place.x, place.y, place.id)); }); // Create the edges with their nodes edgeData.forEach((edge)=>{ edges.push(new Edge(places[edge.node1.id-1], places[edge.node2.id-1], edges.length+1 )); }); // Update nodes with their edges edges.forEach((edge)=>{ edge.node1.edges.push(edge); edge.node2.edges.push(edge); }); /** * Wiki - Associate with each vertex v of the graph a number C[v] (the cheapest cost of a connection to v) * and an edge E[v] (the edge providing that cheapest connection). 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Answer 1

更具体地说，

C [v]是最便宜的传入边缘，而其他端点不属于Q 。初始化应该是

            place.C = Infinity;
            place.E = null;

来自Wikipedia 3c的Prims MST没有意义

1 个答案: