【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。

 /* 3451 */
 #include <iostream>
 #include <queue>
 #include <cstdio>
 #include <cstring>
 #include <cstdlib>
 using namespace std;

 #define MAXN 105

 typedef struct node_t{
     int x,y,d,t;
     node_t() {}
     node_t(int xx, int yy, int dd, int tt) {
         x = xx; y = yy; d = dd; t = tt;
     }
 } node_t;

 node_t beg;
 int bx, by;
 int n, m, l;
 int map[MAXN][MAXN];
 int t[MAXN][MAXN];
 int dir[][] = {
     -,,,,,-,,
 };

 inline bool check(int x, int y) {
     return x< || x>=n || y< || y>=m;
 }

 bool isValid() {
     int i, j;

     for (i=; i<n; ++i)
         for (j=; j<m; ++j)
             if (map[i][j])
                 return false;
     return true;
 }

 void bfs() {
     int x, y, d;
     int i, j, k;
     node_t nd;
     queue<node_t> Q;

     memset(t, , sizeof(t));
     if (map[bx][by] == l) {
         map[bx][by] = ;
         t[bx][by] = ;
         nd.t = ;
         for (i=; i<; ++i) {
             nd.x = bx + dir[i][];
             nd.y = by + dir[i][];
             if (check(nd.x, nd.y))
                 continue;
             nd.d = i;
             Q.push(nd);
         }
     } else {
         ++map[bx][by];
         return ;
     }

     while (!Q.empty()) {
         nd = Q.front();
         Q.pop();
         if (map[nd.x][nd.y] == l) {
             // break
             map[nd.x][nd.y] = ;
             t[nd.x][nd.y] = nd.t;
             for (i=; i<; ++i) {
                 x = nd.x + dir[i][];
                 y = nd.y + dir[i][];
                 if (check(x, y))
                     continue;
                 Q.push(node_t(x, y, i, nd.t+));
             }
         } else if (map[nd.x][nd.y]) {
             // absorb
             ++map[nd.x][nd.y];
         } else if (t[nd.x][nd.y] != nd.t) {
             // no drop, continue fly
             x = nd.x + dir[nd.d][];
             y = nd.y + dir[nd.d][];
             if (check(x, y))
                 continue;
             Q.push(node_t(x, y, nd.d, nd.t+));
         }
     }
 }

 int main() {
     int t;
     int i, j, k;
     bool flag;

     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
         freopen("data.out", "w", stdout);
     #endif

     scanf("%d", &t);
     while (t--) {
         scanf("%d %d %d", &n, &m, &l);
         flag = false;
         for (i=; i<n; ++i) {
             for (j=; j<m; ++j) {
                 scanf("%d", &map[i][j]);
             }
         }
         flag = isValid();
         scanf("%d", &k);
         while (k--) {
             scanf("%d %d", &bx, &by);
             --bx; --by;
             if (flag == false) {
                 bfs();
                 flag = isValid();
             }
         }
         if (flag) {
             puts("YES");
         } else {
             puts("NO");
             for (i=; i<n; ++i) {
                 for (j=; j<m; ++j)
                     printf("%d ", map[i][j]);
                 printf("\n");
             }
         }
     }

     return ;
 }