话不多说，看代码

#include<bits/stdc++.h>
using namespace std;
struct node{
	int x,y;
}z;
node dlt;
int yx[4]={1,-1,2,-2};
int yy[4]={1,-1,2,-2};
bool vis[405][405];
int a[405][405];
int n,m,xg,yg;
queue <node> q;
void bfs(int x,int y,int step){
	a[x][y]=step;
	vis[x][y]=false;
	queue<node> q;
	z.x=x;
	z.y=y;
	q.push(z);
	while(!q.empty()){
		dlt=q.front();
		q.pop();
		for(int i=0;i<4;i++){
			for(int j=0;j<4;j++){
				if(abs(yx[i])!=abs(yy[j])){
					int newx=dlt.x+yx[i];
					int newy=dlt.y+yy[j];
					if(newx<1 || newx>n || newy<1 || newy>m) continue;
					if(vis[newx][newy]){
						z.x=newx;
						z,y=newy;
						q.push(z);
						vis[newx][newy]=false;
						a[newx][newy]=a[dlt.x][dlt.y]+1;	
					} 
				}
			}
		}
	}
}
int main(){
	memset(vis,true,sizeof(vis));
	memset(a,-1,sizeof(a));
	cin>>n>>m>>xg>>yg;
	bfs(xg,yg,0);
	for(int i=1;i<=n;i++){
		for(int j=1;j<=m;j++){
			printf("%-5d",a[i][j]);
		}
		cout<<endl;
	}
	return 0;
} 

附：样例测试 输入3 3 1 1

输出： 0 0 0

-1 -1 1

-1 1 0