【HDOJ】3451 Beat drop

BFS。当水滴破裂飞溅后，直到碰到水滴才会停止（观察case1）。同时，考虑当水滴飞溅到点（x，y）并且该点同一时间破裂的情况，该水滴算作吸收。

  1 /* 3451 */
  2 #include <iostream>
  3 #include <queue>
  4 #include <cstdio>
  5 #include <cstring>
  6 #include <cstdlib>
  7 using namespace std;
  8
  9 #define MAXN 105
 10
 11 typedef struct node_t{
 12     int x,y,d,t;
 13     node_t() {}
 14     node_t(int xx, int yy, int dd, int tt) {
 15         x = xx; y = yy; d = dd; t = tt;
 16     }
 17 } node_t;
 18
 19 node_t beg;
 20 int bx, by;
 21 int n, m, l;
 22 int map[MAXN][MAXN];
 23 int t[MAXN][MAXN];
 24 int dir[4][2] = {
 25     -1,0,1,0,0,-1,0,1
 26 };
 27
 28 inline bool check(int x, int y) {
 29     return x<0 || x>=n || y<0 || y>=m;
 30 }
 31
 32 bool isValid() {
 33     int i, j;
 34
 35     for (i=0; i<n; ++i)
 36         for (j=0; j<m; ++j)
 37             if (map[i][j])
 38                 return false;
 39     return true;
 40 }
 41
 42 void bfs() {
 43     int x, y, d;
 44     int i, j, k;
 45     node_t nd;
 46     queue<node_t> Q;
 47
 48     memset(t, 0, sizeof(t));
 49     if (map[bx][by] == l) {
 50         map[bx][by] = 0;
 51         t[bx][by] = 1;
 52         nd.t = 2;
 53         for (i=0; i<4; ++i) {
 54             nd.x = bx + dir[i][0];
 55             nd.y = by + dir[i][1];
 56             if (check(nd.x, nd.y))
 57                 continue;
 58             nd.d = i;
 59             Q.push(nd);
 60         }
 61     } else {
 62         ++map[bx][by];
 63         return ;
 64     }
 65
 66     while (!Q.empty()) {
 67         nd = Q.front();
 68         Q.pop();
 69         if (map[nd.x][nd.y] == l) {
 70             // break
 71             map[nd.x][nd.y] = 0;
 72             t[nd.x][nd.y] = nd.t;
 73             for (i=0; i<4; ++i) {
 74                 x = nd.x + dir[i][0];
 75                 y = nd.y + dir[i][1];
 76                 if (check(x, y))
 77                     continue;
 78                 Q.push(node_t(x, y, i, nd.t+1));
 79             }
 80         } else if (map[nd.x][nd.y]) {
 81             // absorb
 82             ++map[nd.x][nd.y];
 83         } else if (t[nd.x][nd.y] != nd.t) {
 84             // no drop, continue fly
 85             x = nd.x + dir[nd.d][0];
 86             y = nd.y + dir[nd.d][1];
 87             if (check(x, y))
 88                 continue;
 89             Q.push(node_t(x, y, nd.d, nd.t+1));
 90         }
 91     }
 92 }
 93
 94 int main() {
 95     int t;
 96     int i, j, k;
 97     bool flag;
 98
 99     #ifndef ONLINE_JUDGE
100         freopen("data.in", "r", stdin);
101         freopen("data.out", "w", stdout);
102     #endif
103
104     scanf("%d", &t);
105     while (t--) {
106         scanf("%d %d %d", &n, &m, &l);
107         flag = false;
108         for (i=0; i<n; ++i) {
109             for (j=0; j<m; ++j) {
110                 scanf("%d", &map[i][j]);
111             }
112         }
113         flag = isValid();
114         scanf("%d", &k);
115         while (k--) {
116             scanf("%d %d", &bx, &by);
117             --bx; --by;
118             if (flag == false) {
119                 bfs();
120                 flag = isValid();
121             }
122         }
123         if (flag) {
124             puts("YES");
125         } else {
126             puts("NO");
127             for (i=0; i<n; ++i) {
128                 for (j=0; j<m; ++j)
129                     printf("%d ", map[i][j]);
130                 printf("\n");
131             }
132         }
133     }
134
135     return 0;
136 }