一个有趣的递归例子

Question

public class Recursion2{
int [][] map={{0,0,0,0,0,0,0,1,1,0},
{0,1,1,1,1,1,0,1,0,0},
{1,0,0,0,0,1,0,1,1,0},
{0,0,0,0,1,1,0,0,1,1},
{0,1,1,0,0,1,0,1,1,0},
{0,0,1,1,1,1,0,0,1,0},
{1,0,0,0,0,1,1,1,1,0},
{0,1,0,0,0,1,0,1,1,0},
{0,0,1,1,1,1,1,0,0,0},
{1,0,0,0,0,0,0,0,1,0},};

void checkXY(int x,int y){
if(x>=0&&x<=9&&y>=0&&y<=9&&map[x][y]==1){
map[x][y]=2;
check(x,y);
}
}
void check(int x,int y){
if(map[x][y]==0)return;
checkXY(x-1,y);
checkXY(x+1,y);
checkXY(x,y-1);
checkXY(x,y+1);
}
void printMap(){
for(int i=0;i<10;i++){
for(int j=0;j<10;j++)
System.out.print(map[i][j]);
System.out.println();
}
}
public static void main(String[]args){}
Recursion2 ob=new Recursion2();
ob.check(1,3);
ob.printMap();

Answer 1

//更改下，应该是这样
public class Recursion2{
int [][] map={{0,0,0,0,0,0,0,1,1,0},
{0,1,1,1,1,1,0,1,0,0},
{1,0,0,0,0,1,0,1,1,0},
{0,0,0,0,1,1,0,0,1,1},
{0,1,1,0,0,1,0,1,1,0},
{0,0,1,1,1,1,0,0,1,0},
{1,0,0,0,0,1,1,1,1,0},
{0,1,0,0,0,1,0,1,1,0},
{0,0,1,1,1,1,1,0,0,0},
{1,0,0,0,0,0,0,0,1,0},};

void checkXY(int x,int y){
if(x>=0&&x<=9&&y>=0&&y<=9&&map[x][y]==1){
map[x][y]=2;
check(x,y);
}
}
void check(int x,int y){
if(map[x][y]==0)return;
checkXY(x-1,y);
checkXY(x+1,y);
checkXY(x,y-1);
checkXY(x,y+1);
}
void printMap(){
for(int i=0;i<10;i++){
for(int j=0;j<10;j++)
System.out.print(map[i][j]);
System.out.println();
}
}
public static void main(String[]args){
Recursion2 ob=new Recursion2();
ob.check(1,3);
ob.printMap();
}

}