rt,代码如下：

#include<bits/stdc++.h>
using namespace std;
int a[8][2]={{2,1},{2,-1},{-2,1},{-2,-1},{1,2},{1,-2},{-1,2},{-1,-2}}; 
struct coord{
	int x,y;
};
queue<int> q;
int main(){
	int n,m,x1,y1;
	cin>>n>>m>>x1>>y1;
	int ans[x1+1][y1+1];
	memset(ans,-1,sizeof(ans));
	coord tmp={x1,y1};
	q.push(tmp);
	ans[x1][y1]=0; 
	while(!q.empty()){
		coord b=q.front();
		int x2=b.x,y2=b.y;
		for(int i=0;i<=1;i++){
			int x3=x2+a[i],y3=y2+a[i],c=ans[x3][y3];
			if(x3<1||x3>n||y3<1||y3>n||ans!=-1)continue;
			ans[x3][y3]=d+1;
			coord tmp={x3,y3};
			q.push(x3,y3);
		}
	}
	for(int i=1;i<=n;i++,cout<<' '<<endl)
		for(int j=1;j<=m;j++)
			printf("%-5d",ans[i][j]);
  	return 0;
}