【HDOJ】1547 Bubble Shooter

两次BFS，一次扫描关联点。一次扫描可能掉落的情况（即再次扫描所有非爆炸的联通点）。余下未被扫描的点均爆炸。

 #include <cstdio>
 #include <cstring>
 #include <queue>
 #include <cstdlib>
 #include <iostream>
 using namespace std;
 
 #define MAXN 105
 char map[MAXN][MAXN];
 bool visit[MAXN][MAXN];
 int h, w, x, y;
 int dir[][] = {-,, ,, -,, ,, ,, ,-, -,-, ,-};
 
 typedef struct node_t {
     int x, y;
     node_t() {}
     node_t(int xx, int yy) {
         x = xx; y = yy;
     }
 } node_t;
 
 bool check(int x, int y) {
     int ww = w;
 
     if ((x&) == )
         ww = w-;
     if (x< || x>h || y< || y>ww || visit[x][y])
         return true;
     return false;
 }
 
 void bfs_Oth(int x, int y) {
     int i, j, nx, ny;
     queue<node_t> Q;
 
     visit[x][y] = true;
     Q.push(node_t(x,y));
 
     while (!Q.empty()) {
         node_t nd = Q.front();
         Q.pop();
         j = (nd.x & )<<;
         for (i=j; i<j+; ++i) {
             nx = nd.x + dir[i][];
             ny = nd.y + dir[i][];
             if (check(nx, ny) || map[nx][ny]=='E')
                 continue;
             Q.push(node_t(nx, ny));
             visit[nx][ny] = true;
         }
     }
 }
 
 void bfs() {
     int ans = ;
     int i, j, nx, ny;
     char c = map[x][y];
     queue<node_t> Q;
 
     memset(visit, false, sizeof(visit));
     visit[x][y] = true;
     Q.push(node_t(x,y));
 
     while (!Q.empty()) {
         node_t nd = Q.front();
         Q.pop();
         ++ans;
         j = (nd.x & )<<;
         for (i=j; i<j+; ++i) {
             nx = nd.x + dir[i][];
             ny = nd.y + dir[i][];
             if (check(nx, ny) || map[nx][ny]!=c)
                 continue;
             Q.push(node_t(nx, ny));
             visit[nx][ny] = true;
         }
     }
 
     if (ans < ) {
         printf("0\n");
         return ;
     }
 
     // search the other bubbles
     for (j=; map[][j]; ++j) {
         if (!visit[][j] && map[][j]!='E') {
             bfs_Oth(, j);
         }
     }
 
     for (i=; i<=h; ++i) {
         for (j=; map[i][j]; ++j) {
             if (!visit[i][j] && map[i][j]!='E')
                 ++ans;
         }
     }
     printf("%d\n", ans);
 }
 
 int main() {
     int i, j;
 #ifndef ONLINE_JUDGE
     FILE *fin = freopen("data.in", "r", stdin);
 #endif
     while (scanf("%d%d%d%d", &h,&w,&x,&y)!=EOF) {
         for (i=; i<=h; ++i) {
             scanf("%s", map[i]+);
         }
         bfs();
 #ifndef ONLINE_JUDGE
         fflush(stdout);
 #endif
     }
 
     return ;
 }