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這樣做的目的是在選擇其中一個合法的選項之前弄清楚哪些動作是合法的，以暴力推動騎士之旅。我是新來的Java，但我覺得我的錯誤是我無法理解如何處理這個問題：找不到我的OutOfBoundsException
import java.util.*;
public class KnightTour
{
public static void main(String[] args)
{
KnightTour kt = new KnightTour(8, 8);
int tries = 3;
int tryCount = 0;
while(tryCount < tries)
{
kt.makeMoves();
}
}
int rows = 0; //change to args later
int columns = 0; //change to args later
int tries = 0; //change to args later
String[][] saves;
int tryCount = 0;
int turnNr = 2;
int wait = 0;
Random rand = new Random();
int xCurrent = 1;
int yCurrent = 1;
int[] xMoves = { 1, 2, -1, -2, 1, 2, -1, -2 };
int[] yMoves = { 2, 1, 2, 1, -2, -1, -2, -1 };
public KnightTour(int x, int y)
{
rows = x;
columns = y;
saves = new String[y][x];
for (int i = 0; i < y; i++)
{
for (int j = 0; j < x; j++)
{
saves[i][j] = Integer.toString(0);
}
}
saves[0][0] = Integer.toString(1);
}
private void makeMoves()
{
int k = 0;
while(k < (rows * columns))
{
int[] d = { 0, 0, 0, 0, 0, 0, 0, 0 }; // holds move legality
int i = 0;
while(i < d.length) // loop determines which moves are legal
{
if(xCurrent + xMoves[ i ] > 0 && xCurrent + xMoves[ i ] < rows)
{
if(xCurrent + yMoves[ i ] > 0 && yCurrent + yMoves[ i ] < rows)
d[ i ] = 1;
}
i++;
}
int t = 0;
int w = 0;
while(t < d.length) // checks if no moves are legal
{
if(d[ t ] == 0)
{
w++;
}
t++;
}
if(w == 8)
{
writeFailures(); // fills the rest of the grid with "x"'s
k = (rows * columns); // breaks the loop
}
else
{
w = 0;
chooseMove(d);
}
k++;
}
printSolution();
}
private void chooseMove(int[] d) // chooses a move that was previously determined to be legal randomly and checks if it is available
{
System.out.println("trace");
Random rand = new Random();
int r = rand.nextInt(8);
switch(r)
{
case 0:
if(d[ 0 ] == 1)
{
setX(xCurrent + xMoves[ 0 ]);
setY(yCurrent + yMoves[ 0 ]);
saves[yCurrent][xCurrent] = Integer.toString(turnNr);
turnNr++;
}
else
{
chooseMove(d);
}
break;
case 1:
if(d[ 1 ] == 1)
{
setX(xCurrent + xMoves[ 1 ]);
setY(yCurrent + yMoves[ 1 ]);
saves[yCurrent][xCurrent] = Integer.toString(turnNr);
turnNr++;
}
else
{
chooseMove(d);
}
break;
case 2:
if(d[ 2 ] == 1)
{
setX(xCurrent + xMoves[ 2 ]);
setY(yCurrent + yMoves[ 2 ]);
saves[yCurrent][xCurrent] = Integer.toString(turnNr);
turnNr++;
}
else
{
chooseMove(d);
}
break;
case 3:
if(d[ 3 ] == 1)
{
setX(xCurrent + xMoves[ 3 ]);
setY(yCurrent + yMoves[ 3 ]);
saves[yCurrent][xCurrent] = Integer.toString(turnNr);
turnNr++;
}
else
{
chooseMove(d);
}
break;
case 4:
if(d[ 4 ] == 1)
{
setX(xCurrent + xMoves[ 4 ]);
setY(yCurrent + yMoves[ 4 ]);
saves[yCurrent][xCurrent] = Integer.toString(turnNr); // LINE 166
turnNr++;
}
else
{
chooseMove(d);
}
break;
case 5:
if(d[ 5 ] == 1)
{
setX(xCurrent + xMoves[ 5 ]);
setY(yCurrent + yMoves[ 5 ]);
saves[yCurrent][xCurrent] = Integer.toString(turnNr);
turnNr++;
}
else
{
chooseMove(d);
}
break;
case 6:
if(d[ 6 ] == 1)
{
setX(xCurrent + xMoves[ 6 ]);
setY(yCurrent + yMoves[ 6 ]);
saves[yCurrent][xCurrent] = Integer.toString(turnNr);
turnNr++;
}
else
{
chooseMove(d);
}
break;
case 7:
if(d[ 7 ] == 1)
{
setX(xCurrent + xMoves[ 7]);
setY(yCurrent + yMoves[ 7 ]);
saves[yCurrent][xCurrent] = Integer.toString(turnNr);
turnNr++;
}
else
{
chooseMove(d);
}
break;
default:
System.out.println("error");
}
}
public int getX()
{
return xCurrent;
}
public void setX(int x)
{
xCurrent = x;
}
public int getY()
{
return yCurrent;
}
public void setY(int y)
{
yCurrent = y;
}
private void writeFailures() // writes an "x" to empty spots in the save array when no legal moves are found
{
for (int i = 0; i < saves.length; i++)
{
for (int j = 0; j < saves[i].length; j++)
{
if(saves[i][j] == "0");
saves[i][j] = "x";
}
}
}
private void printSolution()
{
for (int i = 0; i < saves.length; i++)
{
for (int j = 0; j < saves[i].length; j++)
{
System.out.print(saves[i][j] + " ");
}
System.out.println("");
}
System.out.println("");
}
}
我得到的錯誤是：
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -2
at KnightTour.chooseMove(KnightTour.java:166)
at KnightTour.makeMoves(KnightTour.java:91)
at KnightTour.main(KnightTour.java:14)
編輯：現在代碼行號是好的。
會，如果你是有益的可以說哪一行是166 –