【发布时间】：2022-01-03 00:09:35
【问题描述】：
当我运行程序而不是找到 Knights Tour 时，我收到了 StackOverflow 错误。知道是什么原因造成的，以及如何更改我的代码以实际找到 Knights Tour 并摆脱此错误。项目适用于我的 CS280 课程，将于周五到期，请帮忙。谢谢！！
public class KnightsTourDriver {
public static void main (String[]args) {
KnightsTour tour1 = new KnightsTour;
tour1.findTour(1);
tour1.displayTour();
}
}
import java.util.Arrays;
class KnightsTour
{
static int the_board[][] = new int[8][8];
int the_tour[][] = new int [8][8];
int k,moves = 0;
int x = 0, y = 0;
int z, j = 1;
boolean tour_found, isSafe;
//fills 2D array with 0's
public KnightsTour()
{
for (int i = 0; i < 8; i++)
{
for (int r = 0; r < 8; r++)
{
the_board[i][r] = 0;
}
}
}
/*recursive method, checks how many moves were made if 16 were made tour finished,
else if not moves knight checks if the move is valid if not back tracks*/
public void findTour(int q)
{
if(moves == 64)
{
tour_found = true;
}
else
move(q);
if(isSafe == true)
{
findTour(q++);
moves++;
}
else
if(isSafe == false)
{
findTour(q*(-1));
moves--;
}
}
//used to keep prevent arrayindexoutofbounds error
public boolean arrayInBounds(int x, int y)
{
if(x < 8 && y < 8 && x >= 0 && y >= 0)
{
return true;
}
else return false;
}
/*move method uses switch statement to decide which move the knight should make
based on a case number, negative case numbers back track knight. if statement checks
if the current array element is empty and the index is inbounds*/
public void move(int a)
{
switch (a)
{
case 1:
if(arrayInBounds(x+2, y+1) == true){
if(the_board[x+2][y+1] != 0){
the_board[x+2][y+1]=j;
j++;
break;
}
else isSafe = false;
break;
}
else isSafe = false;
case 2:
if (arrayInBounds(x+1, y+2) == true){
if(the_board[x+1][y+2] != 0){
the_board[x+1][y+2]=j;
j++;
break;
}
else isSafe = false;
break;
}
else isSafe = false;
case 3:
if(arrayInBounds(x-1, y+2) == true){
if(the_board[x-1][y+2] != 0){
the_board[x-1][y+2]=j;
j++;
break;
}
else isSafe = false;
break;
}
else isSafe = false;
case 4:
if (arrayInBounds(x-2, y+1) == true){
if(the_board[x-2][y+1] != 0){
the_board[x-2][y+1]=j;
j++;
break;
}
else isSafe = false;
break;
}
else isSafe = false;
case 5:
if(arrayInBounds(x-2, y-1) == true){
if(the_board[x-2][y-1] != 0){
the_board[x-2][y-1]=j;
j++;
break;
}
else isSafe = false;
break;
}
else isSafe = false;
case 6:
if(arrayInBounds(x-1, y-2) == true){
if(the_board[x-1][y-2] != 0){
the_board[x-1][y-2]=j;
j++;
break;
}
else isSafe = false;
break;
}
else isSafe = false;
case 7:
if(arrayInBounds(x+1, y-2) == true){
if(the_board[x+1][y-2] != 0){
the_board[x+1][y-2]=j;
j++;
break;
}
else isSafe = false;
break;
}
else isSafe = false;
case 8:
if(arrayInBounds(x+2, y-1) == true){
if(the_board[x+2][y-1] != 0){
the_board[x+2][y-1]=j;
j++;
break;
}
else isSafe = false;
break;
}
else isSafe = false;
case -1:
j--;
tryNextMove(a);
break;
case -2:
j--;
tryNextMove(a);
break;
case -3:
j--;
tryNextMove(a);
break;
case -4:
j--;
tryNextMove(a);
break;
case -5:
j--;
tryNextMove(a);
break;
case -6:
j--;
tryNextMove(a);
break;
case -7:
j--;
tryNextMove(a);
break;
case -8:
j--;
tryNextMove(a);
break;
}
}
public void tryNextMove(int m)
{
move(m++);
}
//for loop to display tour once found//
public void displayTour()
{
int v = 1;
for (int i = 0; i < 8; i++)
{
for (int e = 0; e < 8; e++)
{
if(v % 8 == 0)
{
System.out.print(the_board[i][e] + "\t");
System.out.println("\n");
}
else
System.out.print(the_board[i][e] + "\t");
v++;
}
}
}
}
【问题讨论】：
-
堆栈跟踪会很好，但如果您自己调试它，那将比我们提供的任何答案更能帮助您。
-
查看
if方法中的第一组findTour条件；是否有一条路径不会再次递归调用findTour？ -
请了解后自增和前自增运算符。也许你会看到你的错误。
-
你介意把它放在一个主要的方法中吗？所以 some1 readng 可以用代码快速播放
-
如何显示堆栈跟踪？
标签： java recursion backtracking knights-tour