我正试图在遍历我的DFS堆栈时尽可能快地运行此代码，目前输入文件是这样的：
0 2 2 1 1 4 4 5 5 6 10 8 8 9 9 6 7 6 3 4 0 1 3 9 0 4
我的Maze课程将数字绑定在一起并为我创建图表。在创建图表之后，我的DFS类通过遍历提供给提交的.txt文件的一个或所有解决方案。我最近改变了我的Maze类，因为它运行得更有效但是被抛出错误并且数据正在解析到我的DFS以输出。我的Maze课程如下：
import java.io.*;
import java.util.*;
public class Maze {
private final Map<Integer, Set<Integer>> adjList = new HashMap<>();
/**
* The main constructor that takes a String for reading maze file.
*
* @param file
*/
public Maze(File file) throws FileNotFoundException {
try (Scanner scan = new Scanner(file)) {
while (scan.hasNextInt()) {
int node1 = scan.nextInt();
int node2 = scan.nextInt();
this.connect(node1, node2);
this.connect(node2, node1);
}
}
}
/**
* Makes a unidirectional connection from node1 to node2.
*/
private void connect(int node1, int node2) {
if (!this.adjList.containsKey(node1)) {
this.adjList.put(node1, new HashSet<Integer>());
}
this.adjList.get(node1).add(node2);
}
/**
* Returns a human-readable description of the adjacency lists.
*/
public String toString() {
StringBuilder s = new StringBuilder();
for (Map.Entry<Integer, Set<Integer>> adj : this.adjList.entrySet()) {
int from = adj.getKey();
Set<Integer> to = adj.getValue();
s.append(from).append(" connected to ").append(to).append('\n');
}
return s.toString();
}
/**
* Returns the set of nodes connected to a particular node.
*
* @param node - the node whose neighbors should be fetched
*/
public Iterable<Integer> getadjList(int node) {
return Collections.unmodifiableSet(adjList.get(node));
}
/**
* Demonstration of file reading.
*/
public static void main(String[] args) throws FileNotFoundException {
System.err.print("Enter File: ");
Scanner scanFile = new Scanner(System.in);
String file = scanFile.nextLine();
Maze m = new Maze(new File(file));
System.out.println(m);
}
}
我的DFS看起来就是这样。
import java.util.Scanner;
import java.util.Stack;
public class DFS {
//starting node, the route to the next node, has node been visited
private int startNode;
private int[] route;
private boolean[] visited;
// 2 main arguments - Maze File & user input
public DFS(Maze maze, int inputInt) {
int startNode = 0;
int goalNode = 1;
route = new int[maze.node];
visited = new boolean[maze.node];
//Takes user's input and runs desired function
if(inputInt == 1){
startDFSone(maze, startNode, goalNode);
}
else if (inputInt == 2){
startDFSall(maze, startNode, goalNode);
}
else {
System.out.println("input invalid. No Solution Returned");
}
}
//Put path to goal in the stack
public Stack<Integer> route(int toGoalNode) {
if (!visited[toGoalNode]) {
return null;
}
Stack<Integer> pathStack = new Stack<Integer>();
for (int routeGoalNode = toGoalNode; routeGoalNode != startNode; routeGoalNode = route[routeGoalNode]) {
pathStack.push(routeGoalNode);
}
pathStack.push(startNode);
reverseStack(pathStack);
return pathStack;
}
//Reverse the stack
public void reverseStack(Stack<Integer> stackToBeReverse) {
if (stackToBeReverse.isEmpty()) {
return;
}
int bottom = popBottomStack(stackToBeReverse);
reverseStack(stackToBeReverse);
stackToBeReverse.push(bottom);
}
//Pop the bottom of the stack
private int popBottomStack(Stack<Integer> stackToBeReverse) {
int popTopStack = stackToBeReverse.pop();
if (stackToBeReverse.isEmpty()) {
return popTopStack;
} else {
int bottomStack = popBottomStack(stackToBeReverse);
stackToBeReverse.push(popTopStack);
return bottomStack;
}
}
//performs DFS and unsets visited to give the result of all paths
private void startDFSall(Maze maze, int node, int goal) {
visited[node] = true;
if(node == goal) {
printPath(goal);
} else {
for (int con : maze.getadjList(node)) {
if (!visited[con]) {
route[con] = node;
startDFSall(maze, con, goal);
}
}
}
visited[node] = false;
}
//performs DFS and maintains visited marker giving only one path
private void startDFSone(Maze maze, int node, int goal) {
visited[node] = true;
for (int con : maze.getadjList(node)) {
if (!visited[con]) {
route[con] = node;
startDFSone(maze, con, goal);
}
}
}
//Traverse the connections to the goal and print the path taken
public void printPath( int toGoal) {
int goalNode = 1;
if (visited[toGoal]) {
System.out.println("Completed Path: ");
for (int t : route(toGoal)) {
if (t == toGoal) {
System.out.print(t);
} else {
System.out.print(t + " -> ");
}
}
System.out.println();
}
}
public static void main(String[] args) {
Scanner scanFile = new Scanner(System.in);
int goalNode = 1;
System.out.print("Enter maze file: ");
String file = scanFile.nextLine();
Maze maze = new Maze(file); //**Most error's show here**
Scanner scanInt = new Scanner(System.in);
System.out.print("Enter desired feedback (1 = one soultion, 2 = all): ");
int inputInt = scanInt.nextInt();
maze.toString(); //**Most error's show here**
System.out.println();
DFS dfs = new DFS(maze, inputInt); //**error's show here**
dfs.printPath(goalNode); //**error's show here**
}
}
我已经查看了一段时间，无法弄清楚数据解析和使用的确切原因。我在这里和那里改变了一些东西，但却被抛出了更多的错误。希望有人可以提供任何帮助。感谢
编辑：我认为问题是由于尝试使用文件类型作为字符串我在DFS类的主要部分中标记了我认为问题可能源自哪个
答案 0 :(得分：1)
更改
Maze maze = new Maze(file)
进入
Maze maze = new Maze(new File(file));
但程序仍有其他错误需要修复。 Eclipse，Netbean，intellij或其他一些IDE将为您提供帮助。