```cpp
#include<bits/stdc++.h>
using namespace std;
int sx,sy,n,m;
int a[401][401];
bool vis[401][401];//开bool就够省空间
short dx[9] = {1,-1,1,-1,-2,-2,2,2};
short dy[9] = {-2,-2,2,2,1,-1,1,-1};
struct node{
int x;
int y;
};
queue <node> q;
void bfs()
{
q.push(node{sx,sy});
while (!q.empty())
{
for (int i = 0;i < 8;i++)
{
int xx = q.front().x+dx[i];
int yy = q.front().y+dy[i];
if (xx >= 1 && xx <= n && yy >= 1 && yy <= m && vis[xx][yy] != 1){
vis[xx][yy] = 1;
a[xx][yy] = a[q.front().x][q.front().y] + 1;
q.push(node{xx,yy});
}
}
q.pop();
}
}
int main(){
std::ios::sync_with_stdio(false);//这样cin cout就快了
//cin>>m>>n>>sx>>sy; 额这里有问题你行列没分清然后就AC了其他也不需要改
cin>>n>>m>>sx>>sy;
vis[sx][sy] = 1;
for(int i=1;i<=n;i++)
for(int j=1;j<=m;j++)
a[i][j]=-1;
//memset(a,-1,sizeof(a));
a[sx][sy] = 0;
bfs();
for (int i = 1;i <= n;i++)
{
for (int j = 1;j <= m;j++)
cout<<a[i][j]<<' ';
//printf("%d ",a[i][j]); printf和cin不要一起用占用时间
cout<<endl;
}
return 0;//比赛时记得加
}
```
改好了并进行了部分时间和空间的优化，行列一定要分清！！！！！！
by Augensterm @ 2023-07-11 13:05:34
感谢大佬的回复
by LCX_201109091514 @ 2023-07-25 18:06:33