题目：

代码：

#include<algorithm>
#include<iostream>
#include<cstring>
#include<queue>

using namespace std;

int n,m;

int dx[] = {-1,-1,-2,-2,1,1,2,2};
int dy[] = {-2,2,-1,1,-2,2,-1,1};
bool vis[450][450];

struct node{
	int x,y;
};

int sx,sy;
int mp[450][450] = {-1}; //将路径存在mp里 

void bfs(int xx,int yy){
	queue<node> q;
	q.push({xx,yy});
	vis[xx][yy] = true;
	mp[xx][yy] = 0;
	
	while(!q.empty()){
		node temp = q.front();
		q.pop();
		
		for(int i=0;i<8;i++){
			int nx = dx[i] + temp.x;
			int ny = dy[i] + temp.y;
			
			if(nx > n || nx <= 0 || ny > m || ny <= 0) continue;
			if(vis[nx][ny]) continue;
			if(!vis[nx][ny]){
				vis[nx][ny] = true;
				mp[nx][ny] = mp[temp.x][temp.y] + 1;	
				q.push({nx,ny});			
			}
		}
	}
	
	for(int i=1;i<=n;i++){
		for(int j=1;j<=m;j++){
			printf("%d    ",mp[i][j]);
		}
		printf("\n");
	}
	
}
int main()
{
	scanf("%d%d%d%d",&n,&m,&sx,&sy);
	for(int i=1;i<=n;i++){
		for(int j=1;j<=m;j++){
			mp[i][j] = -1;
		}
	}

	bfs(sx,sy);//要从x,y到达每一个点，不能到达赋值-1
	//用队列，地图赋值-1	
	return 0;
} 

结果：