代码发一下？
by Monkey_Hunter @ 2020-02-27 13:27:04
写错了呗，你不给我们代码，我们怎么知道为什么写错了
by Islauso @ 2020-02-27 13:28:40
~~为什么要写dfs呢~~
by Callous_Murder @ 2020-02-27 13:32:14
~~递推它不香吗~~
by critnos @ 2020-02-27 13:33:03
。
by team109 @ 2020-02-27 13:33:30
代码呢
by 血色黄昏 @ 2020-02-27 13:57:04
递推呀
by zhjzhmh @ 2020-02-27 14:08:17
这是代码
```java
import java.util.Scanner;
public class Main {
static int[][] a = new int[50][50];
static int ans = 0, endx, endy;
static int[] xx = {1,0};
static int[] yy = {0,1};
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
endx = in.nextInt();
endy = in.nextInt();
int hx = in.nextInt();
int hy = in.nextInt();
a[hx][hy] = 1;
if( hx-1>=0 ) a[hx-1][hy+2] = 1;
if( hx-1>=0 && hy-2>=0 ) a[hx-1][hy-2] = 1;
if( hx-2>=0 ) a[hx-2][hy+1] = 1;
if( hx-2>=0 && hy-1>=0 ) a[hx-2][hy-1] = 1;
if( hy-1 >= 0 ) a[hx+2][hy-1] = 1;
if( hy-2>=0 ) a[hx+1][hy-2] = 1;
a[hx+1][hy+2] = 1;
a[hx+2][hy+1] = 1;
dfs(0, 0);
System.out.println(ans);
in.close();
}
public static void dfs(int o, int p) {
int x, y;
if( o==endx && p==endy ) {
ans++;
return;
} else {
for( int i=0; i<2; i++ ) {
x = o + xx[i];
y = p + yy[i];
if( x>=0 && x<=endx && y>=0 && y<=endy && a[x][y]==0 ) {
a[x][y]=1;
dfs(x, y);
a[x][y]=0;
}
}
}
}
}
```
by lyd_try @ 2020-03-07 17:36:34
@[自动WA机私信我](/user/249786)
```java
import java.util.Scanner;
public class Main {
static int[][] a = new int[50][50];
static int ans = 0, endx, endy;
static int[] xx = {1,0};
static int[] yy = {0,1};
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
endx = in.nextInt();
endy = in.nextInt();
int hx = in.nextInt();
int hy = in.nextInt();
a[hx][hy] = 1;
if( hx-1>=0 ) a[hx-1][hy+2] = 1;
if( hx-1>=0 && hy-2>=0 ) a[hx-1][hy-2] = 1;
if( hx-2>=0 ) a[hx-2][hy+1] = 1;
if( hx-2>=0 && hy-1>=0 ) a[hx-2][hy-1] = 1;
if( hy-1 >= 0 ) a[hx+2][hy-1] = 1;
if( hy-2>=0 ) a[hx+1][hy-2] = 1;
a[hx+1][hy+2] = 1;
a[hx+2][hy+1] = 1;
dfs(0, 0);
System.out.println(ans);
in.close();
}
public static void dfs(int o, int p) {
int x, y;
if( o==endx && p==endy ) {
ans++;
return;
} else {
for( int i=0; i<2; i++ ) {
x = o + xx[i];
y = p + yy[i];
if( x>=0 && x<=endx && y>=0 && y<=endy && a[x][y]==0 ) {
a[x][y]=1;
dfs(x, y);
a[x][y]=0;
}
}
}
}
}
```
by lyd_try @ 2020-03-07 17:37:24
@[Segment_Tree_](/user/183235)
```java
import java.util.Scanner;
public class Main {
static int[][] a = new int[50][50];
static int ans = 0, endx, endy;
static int[] xx = {1,0};
static int[] yy = {0,1};
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
endx = in.nextInt();
endy = in.nextInt();
int hx = in.nextInt();
int hy = in.nextInt();
a[hx][hy] = 1;
if( hx-1>=0 ) a[hx-1][hy+2] = 1;
if( hx-1>=0 && hy-2>=0 ) a[hx-1][hy-2] = 1;
if( hx-2>=0 ) a[hx-2][hy+1] = 1;
if( hx-2>=0 && hy-1>=0 ) a[hx-2][hy-1] = 1;
if( hy-1 >= 0 ) a[hx+2][hy-1] = 1;
if( hy-2>=0 ) a[hx+1][hy-2] = 1;
a[hx+1][hy+2] = 1;
a[hx+2][hy+1] = 1;
dfs(0, 0);
System.out.println(ans);
in.close();
}
public static void dfs(int o, int p) {
int x, y;
if( o==endx && p==endy ) {
ans++;
return;
} else {
for( int i=0; i<2; i++ ) {
x = o + xx[i];
y = p + yy[i];
if( x>=0 && x<=endx && y>=0 && y<=endy && a[x][y]==0 ) {
a[x][y]=1;
dfs(x, y);
a[x][y]=0;
}
}
}
}
}
```
by lyd_try @ 2020-03-07 17:37:45