【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[8][2] = {-1,1, 1,1, -1,0, 0,1, 1,0, 0,-1, -1,-1, 1,-1};

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&1) == 0)
        ww = w-1;
    if (x<1 || x>h || y<1 || 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 & 1)<<1;
        for (i=j; i<j+6; ++i) {
            nx = nd.x + dir[i][0];
            ny = nd.y + dir[i][1];
            if (check(nx, ny) || map[nx][ny]=='E')
                continue;
            Q.push(node_t(nx, ny));
            visit[nx][ny] = true;
        }
    }
}

void bfs() {
    int ans = 0;
    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 & 1)<<1;
        for (i=j; i<j+6; ++i) {
            nx = nd.x + dir[i][0];
            ny = nd.y + dir[i][1];
            if (check(nx, ny) || map[nx][ny]!=c)
                continue;
            Q.push(node_t(nx, ny));
            visit[nx][ny] = true;
        }
    }

    if (ans < 3) {
        printf("0
");
        return ;
    }

    // search the other bubbles
    for (j=1; map[1][j]; ++j) {
        if (!visit[1][j] && map[1][j]!='E') {
            bfs_Oth(1, j);
        }
    }

    for (i=1; i<=h; ++i) {
        for (j=1; map[i][j]; ++j) {
            if (!visit[i][j] && map[i][j]!='E')
                ++ans;
        }
    }
    printf("%d
", 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=1; i<=h; ++i) {
            scanf("%s", map[i]+1);
        }
        bfs();
#ifndef ONLINE_JUDGE
        fflush(stdout);
#endif
    }

    return 0;
}