邻接多重表

含义

邻接多重表是无向图的一种存储方式。邻接多重表是邻接表的改进，它把边的两个顶点存放在边表结点中，所有依附于同一个顶点的边串联在同一链表中，由于每条边依附于两个顶点，则每个边表结点同时链接在两个链表中。

目的

解决邻接表存储无向图时同一条边要存储两次的问题。

代码

import java.util.ArrayList;
import java.util.List;

class EdgeArc {
    boolean mark;
    VexNode ivex;
    VexNode jvex;
    EdgeArc ilink;
    EdgeArc jlink;

}

class VexNode {
    String name;
    int data;
    EdgeArc firstEdgeArc;

    public VexNode(String name) {
        this.name = name;
    }
}

public class MultList {
    int[][] graph;
    List<VexNode> vexNodes;

    public MultList(int[][] graph,String[] names) {
        this.graph = graph;
        vexNodes = buildVexNodes(graph,names);
    }

    public List<VexNode> buildVexNodes(int[][] graph, String[] names) {
        List<VexNode> vexNodes = new ArrayList<>();
        boolean[][] book = new boolean[graph.length][graph.length];
        for (int i = 0; i < graph.length; i++) {
            vexNodes.add(new VexNode(names[i]));
        }
        for (int i = 0; i < graph.length; i++) {
            for (int j = 0; j < graph[0].length; j++) {
                if (graph[i][j] == 1) {
                    //有边，那么我们会开始构建
                    if (!book[i][j]) {
                        book[i][j] = book[j][i] = true;
                        EdgeArc edgeArc = new EdgeArc();
                        edgeArc.ivex = vexNodes.get(i);
                        edgeArc.jvex = vexNodes.get(j);
                        buildNextArc(vexNodes.get(i),edgeArc);
                        buildNextArc(vexNodes.get(j),edgeArc);
                    }
                }
            }
        }
        return vexNodes;
    }
    public void buildNextArc(VexNode vexNode,EdgeArc edgeArc){
        if(vexNode.firstEdgeArc==null){
            vexNode.firstEdgeArc = edgeArc;
            return;
        }
        EdgeArc temp = vexNode.firstEdgeArc;
        while (true){
            if(temp.ivex==vexNode){
                if(temp.ilink==null){
                    temp.ilink = edgeArc;
                    return;
                }
                temp = temp.ilink;
                continue;
            }
            if(temp.jvex==vexNode){
                if(temp.jlink==null){
                    temp.jlink = edgeArc;
                    return;
                }
                temp = temp.jlink;
            }
        }
    }
    public void printNodeArc(){
        for(VexNode vexNode:vexNodes){
            System.out.println("节点: "+vexNode.name);
            EdgeArc edgeArc = vexNode.firstEdgeArc;
            while (edgeArc!=null){
                System.out.println(edgeArc.ivex.name+"-----"+edgeArc.jvex.name);
                if(edgeArc.ivex==vexNode){
                    edgeArc = edgeArc.ilink;
                    continue;
                }
                if(edgeArc.jvex==vexNode){
                    edgeArc = edgeArc.jlink;
                }
            }
        }
    }
}
class testMultListNode{
    public static void main(String[] args) {
        String[] names = {"v1","v2","v3","v4"};
        int[][] graph = {{0,1,0,1},{1,0,1,1},{0,1,0,1},{1,1,1,0}};
        MultList multList = new MultList(graph,names);
        multList.printNodeArc();
    }
}