P1443 马的遍历【BFS】

3 3 1 1

0    3    2    
3    -1   1    
2    1    4    

#include <stdio.h>
#include <string.h>
#include<bits/stdc++.h>

using namespace std;
typedef long long ll;
int mp[410][410];
int vis[410][410];
struct node
{
    int x,y,step;
} w,l;

int dx[] = {-1,-1,-2,-2,1,1,2,2};
int dy[] = {-2,2,-1,1,-2,2,1,-1};
void bfs(int sx, int sy,int n, int m)
{
    memset(vis,0,sizeof(vis));
    memset(mp,-1,sizeof(mp));
    queue<node>q;
    w.x = sx;
    w.y = sy;
    w.step = 0;
    q.push(w);
    vis[w.x][w.y] = 1;
    mp[sx][sy] = 0;
    while(!q.empty())
    {
        w = q.front();
        q.pop();
        for(int i = 0; i < 8; i ++)
        {
            int tx = dx[i] + w.x;
            int ty = dy[i] + w.y;
            if(tx >= 1 && tx <= n && ty >= 1 && ty <= m && vis[tx][ty] == 0)
            {
                l.x = tx;
                l.y = ty;
                l.step = w.step+1;
                q.push(l);
                vis[tx][ty] = 1;
                mp[tx][ty] = l.step;
            }
        }
    }
}
int main()
{
    int n,m,sx,sy;
//    cin >> n >> m >> sx >> sy;
    scanf("%d %d %d %d", &n,&m,&sx,&sy);
    bfs(sx,sy,n,m);
    for(int i = 1; i <= n; i ++)
    {
        for(int j = 1; j <= m; j ++)
        {
//            if(j == 1)
//                cout << mp[i][j];
//            else
//                cout << "    " << mp[i][j] ;
            printf("%-5d",mp[i][j]);
        }
        printf("\n");
    }
    return 0;
}