hdu 1175

 1 #include <stdio.h>
 2 #include <string.h>
 3 #include <queue>
 4 #define jud(Node) Node.x>0&&Node.x<m+1&&Node.y>0&&Node.y<n+1
 5 using namespace std;
 6 
 7 struct Node{
 8     int x,y;
 9     int step;
10 };
11 queue<Node>s;
12 int graph[1005][1005];
13 int m,n,t;
14 int a,b,c,d;
15 int mark[1005][1005];
16 int dic[4][2] = {0,1,1,0,0,-1,-1,0};
17 
18 void bfs()
19 {
20     memset(mark,true,sizeof(mark));
21     Node tmp,tmp1;
22     tmp.x = a;
23     tmp.y = b;
24     tmp.step = -1;
25     mark[tmp.x][tmp.y] = false;
26     while(!s.empty())
27         s.pop();
28     s.push(tmp);
29     while(!s.empty())
30     {
31         tmp = s.front();
32         s.pop();
33         if(tmp.x==c&&tmp.y==d&&tmp.step<=2)
34         {
35             printf("YES\n");
36             return;
37         }
38         for(int i = 0; i<4; i++)
39         {
40             tmp1.x = tmp.x + dic[i][0];
41             tmp1.y = tmp.y + dic[i][1];
42             while(((graph[tmp1.x][tmp1.y]==0)||(tmp1.x==c&&tmp1.y==d))&&jud(tmp1)&&tmp.step<2)
43             {
44                 if(mark[tmp1.x][tmp1.y])
45                 {
46                     tmp1.step = tmp.step+1;
47                     mark[tmp1.x][tmp1.y] = false;
48                     s.push(tmp1);
49                    // printf("%d %d %d %d\n",tmp.x,tmp.y,tmp1.x,tmp1.y);
50                 }
51                 Node tmp2;
52                 tmp2.x = tmp1.x+dic[i][0];
53                 tmp2.y = tmp1.y+dic[i][1];
54                 tmp1 = tmp2;
55             }
56         }
57     }
58     printf("NO\n");
59 }
60 
61 int main()
62 {
63 
64     while(scanf("%d%d",&m,&n),m||n)
65     {
66         memset(graph,0,sizeof(graph));
67         for(int i = 1;i<=m;i++)
68             for(int j = 1;j<=n;j++)
69                 scanf("%d",&graph[i][j]);
70         scanf("%d",&t);
71         while(t--)
72         {
73             scanf("%d%d%d%d",&a,&b,&c,&d);
74             if(graph[a][b]==0||graph[c][d]==0)
75                 printf("NO\n");
76             else if(graph[a][b]!=graph[c][d])
77                 printf("NO\n");
78             else if(a==c&&b==d)
79                 printf("NO\n");
80             else bfs();
81         }
82     }
83     return 0;
84 }