@[Lzj_090909](/user/1069781)
$while$ 的判断条件应该是 $!q.empty()$。
改一下就可以 $AC$ 了：
```cpp
#include<cstdio>
#include<cstring>
#include<queue>
using namespace std;
const int walk[8][2]={
{2,1},{-2,1},{2,-1},{-2,-1},{1,2},{-1,2},{1,-2},{-1,-2}
};
struct coord{
int x,y;
};
queue<coord> q;
int book[402][402];
int main(){
int n,m,sx,sy;
scanf("%d%d%d%d",&n,&m,&sx,&sy);
q.push((coord){sx,sy});
memset(book,-1,sizeof(book));
book[sx][sy]=0;
while(!q.empty()){
coord e=q.front(); q.pop();
for(int i=0;i<8;++i){
int x=e.x+walk[i][0],y=e.y+walk[i][1];
if(x<1 || x>n || y<1 || y>m || book[x][y]!=-1)
continue;
book[x][y]=book[e.x][e.y]+1;
q.push((coord){x,y});
}
}
for(int i=1;i<=n;++i,puts(" "))
for(int j=1;j<=m;++j)
printf("%-5d",book[i][j]);
return 0;
}
```
by lqsy002 @ 2024-03-09 13:30:23
啊？！？
不愧是神犇
by Lzj_090909 @ 2024-03-09 21:06:32
@[lqsy002](/user/1216630) 已关
**此帖结**
by Lzj_090909 @ 2024-03-09 21:07:50