【HDOJ】1175 连连看

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <queue>
 5 using namespace std;
 6 
 7 typedef struct node_st{
 8     int x, y;
 9     int dir;
10     int turn;
11     node_st() {}
12     node_st(int xx, int yy, int ddir, int tturn) {
13         x = xx; y = yy; dir = ddir; turn = tturn;
14     }
15 } node_st;
16 
17 int map[1005][1005];
18 int n, m;
19 int dirs[4][2] = {{0,1},{0,-1},{1,0},{-1,0}};
20 char turns[1005][1005];
21 
22 bool bfs(int bx, int by, int ex, int ey) {
23     queue<node_st> que;
24     bool val = false;
25     node_st node;
26     int x, y, dir, turn;
27 
28     memset(turns, 0, sizeof(turns));
29     turns[bx][by] = 1;
30     que.push(node_st(bx, by, -1, 0));
31 
32     while ( !que.empty() ) {
33         node = que.front();
34         //printf("x=%d, y=%d, dir=%d, turn=%d\n", node.x, node.y, node.dir, node.turn);
35         if (node.x == ex && node.y == ey) {
36             val = true;
37             break;
38         }
39         que.pop();
40         for (int i=0; i<4; ++i) {
41             x = node.x + dirs[i][0];
42             y = node.y + dirs[i][1];
43             dir = i;
44             turn = node.turn;
45             if (x<1 || x>n || y<1 || y>m)
46                 continue;
47             if (map[x][y] && (x!=ex || y!=ey))
48                 continue;
49             if (dir!=node.dir && node.dir!=-1)
50                 ++turn;
51             //printf("\tx=%d, y=%d, dir=%d, turn=%d\n", x, y, dir, turn);
52             if (turn > 2)
53                 continue;
54             if (turns[x][y]==0 || turn+1 <= turns[x][y]) {
55                 turns[x][y] = turn+1;
56                 que.push(node_st(x, y, dir, turn));
57             }
58         }
59     }
60 
61     return val;
62 }
63 
64 int main() {
65     int q, x1, x2, y1, y2;
66     int i, j;
67 
68     while (scanf("%d %d", &n, &m)!=EOF && (n||m)) {
69         for (i=1; i<=n; ++i)
70             for (j=1; j<=m; ++j)
71                 scanf("%d", &map[i][j]);
72         scanf("%d", &q);
73         while (q--) {
74             scanf("%d %d %d %d", &x1, &y1, &x2, &y2);
75             if (x1==x2 && y1==y2) {
76                 printf("NO\n");
77                 continue;
78             }
79             if (map[x1][y1]!=map[x2][y2] || map[x1][y1]==0 || map[x2][y2]==0) {
80                 printf("NO\n");
81                 continue;
82             }
83             if ( bfs(x1, y1, x2, y2) )
84                 printf("YES\n");
85             else
86                 printf("NO\n");
87         }
88     }
89 
90     return 0;
91 }