树遍历-运行后将节点追加到邻接矩阵

Question

I'm building a Tree traversal program which allows users to run BFS and DFS traversals, as well as add and remove nodes.

What I'm stuck on is adding nodes due to problems expanding the adjacency matrix. For this example, I'd like to add a new child node X to parent H :

For now, I've hard coded the node X , but will allow for custom input later.

User clicks Add Node button:

    //try and create and connect node via button
AddButton.addActionListener(new ActionListener() {   
        public void actionPerformed(ActionEvent e)
        {   
            Nodes nX = new Nodes("X", nodeX, nodeY, nodeWidth, nodeHeight);
            appendNode(rootNode, nX);
        }
   });

Which calls appendNode(): This function is supposed to be creating a new adjacency matrix with the updated size (given the additional node X )... copying the data from the old matrix adjMatrix , then adding an additional slot for th new node X .

public void appendNode(Nodes parent, Nodes child) {
    //add new node X to nodeList
    addNode(child);

    //loop through all nodes again to be connected, plus new one... then create new adjMatrix
    int newSize = nodeList.size();

    //make a new adj matrix of the new size...
    int[][] adjMatrixCopy = new int[newSize][newSize];

    int fromNode = nodeList.indexOf(parent);
    int toNode = nodeList.indexOf(child);

    //copy adjMatrix data to new matrix...
    for (int i = 0; i < adjMatrix.length; i++) {    
        for (int j = 0; j < adjMatrix[i].length; j++) {
            adjMatrixCopy[i][j] = adjMatrix[i][j];
        }
    }
    for (int col = 0; col < newSize; col++) {
        adjMatrixCopy[newSize][col] = 1;
    }
//  still need to add newly added node 

//  adjMatrixCopy[fromNode][toNode] = 1;
//  adjMatrixCopy[toNode][fromNode] = 0;
//  adjMatrix = null;
}

When I click appendNode , it throws this error:

Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: 12
    at Graph.appendNode(Graph.java:306)
    at Graph$3.actionPerformed(Graph.java:141)

Answer 1

 adjMatrixCopy[newSize][col] = 1;

This is wrong. Maybe you want

 adjMatrixCopy[newSize - 1][col] = 1;

instead?