记录编号	570970	评测结果	AAAAAAAAAAAAA
题目名称	[USACO Feb07] 青铜莲花池	最终得分	100
用户昵称	┭┮﹏┭┮	是否通过	通过
代码语言	C++	运行时间	0.000 s
提交时间	2022-04-28 19:53:58	内存使用	0.00 MiB

#include <bits/stdc++.h>
using namespace std;
int n,m,n1,m1,x2,y2,x3,y3,l,r,s;
int a[50][50],x[10],y[10],b[500][3];
bool v[50][50];
void bfs(){
    while(l < r){
        for(int i = 1;i <= 8;i++){
            int x4 = b[l][0]+x[i],y4 = b[l][1]+y[i];
            if(a[x4][y4] == 0 || x4 < 1 || x4 > m || y4 < 1 || y4 > n || v[x4][y4])continue;
            v[x4][y4] = 1;
            b[r][0] = x4,b[r][1] = y4,b[r][2] = b[l][2] + 1;
            r++;
            if(x4 == x3 && y3 == y4){     
                printf("%d\n",b[r-1][2]);
                break;
            }
        }
        l++;
    }
}
int main(){
    freopen("bronlily.in","r",stdin);
    freopen("bronlily.out","w",stdout);
    scanf("%d%d%d%d",&m,&n,&m1,&n1);
    x[1] = n1,x[2] = n1,x[3] = -n1,x[4] = -n1,x[5] = m1,x[6] = m1,x[7] = -m1,x[8] = -m1;
    y[1] = m1,y[2] = -m1,y[3] = m1,y[4] = -m1,y[5] = n1,y[6] = -n1,y[7] = n1,y[8] = -n1;
    for(int i = 1;i <= m;i++){
        for(int j = 1;j <= n;j++){
            scanf("%d",&a[i][j]);
            if(a[i][j] == 3)x2 = i,y2 = j;
            else if(a[i][j] == 4)x3 = i,y3 = j;
            else if(a[i][j] != 1)a[i][j] = 0;
        }
    }
    b[0][0] = x2,b[0][1] = y2;
    v[x2][y2] = 1;
    r++;
    bfs();
    
    return 0;
}