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私はJavaでAdjacencyMatrixを実装しましたが、2つのノード間の距離を見つけるためにdistance()メソッドを実装するのは苦労しています。 どのように私はそれを行うか? 私はたくさんのことを試しましたが、私は正しい答えを得ることができないようです。AdjacencyMatrixのノード間の距離を計算する
はここで距離を除く
public class AdjacencyMatrix implements Representation {
private Node[] nodes;
private int[][] adjacencyMatrix;
private int numberOfNodes =0;
public AdjacencyMatrix(File file) {
Scanner inFile;
int numNodes;
try {
inFile = new Scanner(file);
numNodes = Integer.parseInt(inFile.nextLine());
adjacencyMatrix = new int[20][20];
nodes = new Node[20];
String[] line;
while (inFile.hasNextLine()) {
line = inFile.nextLine().split(":");
Node from = new Node(Integer.parseInt(line[0]));
Node to = new Node(Integer.parseInt(line[1]));
int value = Integer.parseInt(line[2]);
if(!Arrays.asList(nodes).contains(from))
addNode(from);
if(!Arrays.asList(nodes).contains(to))
addNode(to);
addEdge(new Edge(from, to, value));
}
} catch (FileNotFoundException e) {
System.out.print(e.getCause());
}
}
public AdjacencyMatrix() {
}
@Override
public boolean adjacent(Node x, Node y) {
int fromIndex = findIndex(x);
int toIndex = findIndex(y);
if(adjacencyMatrix[fromIndex][toIndex] == 1 || adjacencyMatrix[toIndex][fromIndex] ==1){
return true;
}
return false;
}
@Override
public List<Node> neighbors(Node x) {
ArrayList<Node> neighbors = new ArrayList<>();
int fromIndex = findIndex(x);
if(x.getData().toString().equals("4")) {
System.out.println("FromIndex is: " + fromIndex);
}
if(x.getData().toString().equals("4")){
for(int i =0; i < nodes.length; ++i){
System.out.println(nodes[i] + " ");
}
}
for (int i = 0; i <= numberOfNodes; i++){
if(adjacencyMatrix[fromIndex][i] == 1){
neighbors.add(nodes[i]);
if(x.getData().toString().equals("4")) {
System.out.println("Match!: " + i);
System.out.println("Adding NODE: " + nodes[i]);
}
}
}
int [] nums = new int[neighbors.size()];
for(int i =0; i < nums.length; ++i){
nums[i] = Integer.parseInt(neighbors.get(i).getData().toString());
}
Arrays.sort(nums);
ArrayList<Node> newNeighbors = new ArrayList<>();
for(int i =0; i < nums.length; ++i){
newNeighbors.add(new Node(nums[i]));
}
return newNeighbors;
}
@Override
public boolean addNode(Node x) {
if(Arrays.asList(nodes).contains(x)){
return false;
}
nodes[numberOfNodes] = x;
for (int i = 0; i <= numberOfNodes; i++){
adjacencyMatrix[numberOfNodes][i] = 0;
adjacencyMatrix[i][numberOfNodes] = 0;
}
numberOfNodes++;
return true;
}
@Override
public boolean removeNode(Node x) {
if (!Arrays.asList(nodes).contains(x)) {
return false;
}
for (int k = 0; k < numberOfNodes; k++) {
if (x.equals(nodes[k])) {
//decrement the number of nodes
numberOfNodes--;
for (int i = k; i < numberOfNodes; i++) {
nodes[i] = nodes[i + 1];
}
for (int i = k; i < numberOfNodes; i++) {
for (int j = 0; j <= numberOfNodes; j++) {
adjacencyMatrix[i][j] = adjacencyMatrix[i + 1][j];
}
}
for (int i = k; i < numberOfNodes; i++) {
for (int j = 0; j < numberOfNodes; j++) {
adjacencyMatrix[j][i] = adjacencyMatrix[j][i + 1];
}
}
}
//
}
return true;
}
@Override
public boolean addEdge(Edge x){
int from = Integer.parseInt(x.getFrom().getData().toString());
int to = Integer.parseInt(x.getTo().getData().toString());
int fromIndex = findIndex(x.getFrom());
int toIndex = findIndex(x.getTo());
if(from == 4){
System.out.println("Adding adjecent to 4 -> " + to);
}
if(adjacencyMatrix[fromIndex][toIndex] == 1){
return false;
}
adjacencyMatrix[fromIndex][toIndex] = 1;
return true;
}
@Override
public boolean removeEdge(Edge x) {
int from = Integer.parseInt(x.getFrom().getData().toString());
int to = Integer.parseInt(x.getTo().getData().toString());
int fromIndex = findIndex(x.getFrom());
int toIndex = findIndex(x.getTo());
if(adjacencyMatrix[fromIndex][toIndex] == 0 && adjacencyMatrix[toIndex][fromIndex] ==0){
return false;
}
adjacencyMatrix[fromIndex][toIndex] = 0;
return true;
}
@Override
public int distance(Node from, Node to) {
return 0;
}
@Override
public Optional<Node> getNode(int index) {
return null;
}
@Override
public Collection<Node> getNodes() {
return Arrays.asList(nodes);
}
public int findIndex(Node node)
{
for (int i = 0; i < numberOfNodes; ++i)
if (nodes[i].equals(node))
return i;
return -1;
}}
すべての私の方法を働いている私の実装です()。 正しく実装する方法がわからないので、distance()メソッドで0を返しています。 ご協力いただければ幸いです。
https://ja.wikipedia.org/wiki/Shortest_path_problem – Tempux