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72 lines
1.8 KiB
JavaScript
72 lines
1.8 KiB
JavaScript
/**
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* @fileOverview 基于 prim 获取有向图最大生成树 算法
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* https://zh.wikipedia.org/wiki/%E6%99%AE%E6%9E%97%E5%A7%86%E7%AE%97%E6%B3%95
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* @author huangtonger@aliyun.com
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*/
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const G6 = require('@antv/g6');
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const { Util } = G6;
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let treeNodes = [];
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let treeEdges = [];
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function maxSpanningTree(connectedSubset) {
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const nodes = connectedSubset.nodes;
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const edges = connectedSubset.edges;
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const root = connectedSubset.root;
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const nodeMap = {};
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Util.each(nodes, node => {
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node.to = [];
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node.from = [];
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nodeMap[node.id] = node;
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});
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Util.each(edges, edge => {
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const source = nodeMap[edge.source];
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const target = nodeMap[edge.target];
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source.to.push(edge);
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target.from.push(edge);
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});
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treeNodes = [ root ];
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treeEdges = [];
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while (treeNodes.length !== nodes.length) {
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let maxWeight = -Infinity;
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let maxEdge;
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let direct = 'target';
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Util.each(treeNodes, treeNode => {
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Util.each(treeNode.to, edge => {
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if (treeNodes.indexOf(nodeMap[edge[direct]]) === -1) {
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if (edge.weight > maxWeight) {
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maxWeight = edge.weight;
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maxEdge = edge;
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}
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}
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});
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});
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if (!maxEdge) {
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direct = 'source';
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Util.each(treeNodes, treeNode => {
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Util.each(treeNode.from, edge => {
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if (treeNodes.indexOf(nodeMap[edge[direct]]) === -1) {
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if (edge.weight > maxWeight) {
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maxWeight = edge.weight;
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maxEdge = edge;
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}
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}
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});
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});
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}
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treeNodes.push(nodeMap[maxEdge[direct]]);
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treeEdges.push(maxEdge);
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}
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// 清除标记
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Util.each(nodes, node => {
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delete node.to;
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delete node.from;
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});
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return {
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nodes: treeNodes,
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edges: treeEdges
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};
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}
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module.exports = maxSpanningTree;
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