如何将带字符串的文本文件读入带邻接列表的无向图

Question

菜鸟来了！我想实现一个类图形，可以表示一个未加权和无向图使用邻接列表。基本功能应该包括添加和删除顶点和边，以及将图形打印到命令行。我的主要问题是我很难将文件读入图表。我做错了什么？

我的文本文件如下所示：

Anna    Noah
Anna    Marie
Marie   Noah
Marie   Jakob
Marie   Hanna
Jakob   Felix
Hanna   Felix
Hanna   Jonas
Felix   Jonas
Felix   Emma
Felix   Finn
Felix   Ben 

（每条线代表由一条边连接的两个节点）。

我的代码是：

public class UndirectedGraphs {
HashMap<String, LinkedList<String>> socialNetworkAdj;

public UndirectedGraphs() {
    socialNetworkAdj = new HashMap<String, LinkedList<String>>();


}
public void addVertex(String label){
    socialNetworkAdj.put(label, new LinkedList<String>());
}

public LinkedList<String> getEdges(String label) {
    return socialNetworkAdj.get(label);
}

public void addEdges(String ver1, String ver2) {
    if (!socialNetworkAdj.containsKey(ver1)) {
        addVertex(ver1);
    }

    if (!socialNetworkAdj.containsKey(ver2)) {
        addVertex(ver2);
    }
    socialNetworkAdj.get(ver1).add(ver2);
    socialNetworkAdj.get(ver2).add(ver1);
    System.out.println(socialNetworkAdj);

}


public static void main(String[] args) throws Exception {

    File filePath = new File("C:\\Users\\Fo\\Desktop\\A9\\network.txt");
    FileReader fr = new FileReader(filePath);
    BufferedReader br = new BufferedReader(fr);

    String[] tokens = new String[2];
    ArrayList<String> nodes = new ArrayList<>();
    UndirectedGraphs graph = new UndirectedGraphs();
    String line;
    String var1 = tokens[0];
    String var2 = tokens[1];

    while ((line = br.readLine()) != null) {
        graph.addEdges(var1, var2);
    }
    System.out.println("\nAnna: --> " + graph.getEdges("Anna"));
    br.close();

}

}

输出为：

{null=[null, null]}
{null=[null, null, null, null]}
{null=[null, null, null, null, null, null]}
{null=[null, null, null, null, null, null, null, null]}
{null=[null, null, null, null, null, null, null, null, null, null]}
{null=[null, null, null, null, null, null, null, null, null, null, null, null]}
{null=[null, null, null, null, null, null, null, null, null, null, null, null, null, 
null]}
{null=[null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null]}
{null=[null, null, null, null, null, null, null, null, null, null, null, null, null, 
null, null, null, null, null]}
{null=[null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null]}
{null=[null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null]}
{null=[null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null]}
{null=[null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null]}
{null=[null, null, null, null, null, null, null, null, null, null, null, null, null, 
null, null, null, null, null, null, null, null, null, null, null, null, null, null, null]}
{null=[null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null]}
{null=[null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null]}

Answer 1

正如注释中指出的，在while循环的每次迭代中，您都需要获取读取行的名称，并在迭代时添加它们。

while((line = br.readLine()) != null) {
    String [] nodes = line.split("\\s+");
    if(nodes.length == 2)
        graph.addEdges(nodes[0], nodes[1]);
    // optional else with error handling
}