FZU-215 (Fire Game)

FZU-215

#include <iostream>
#include <cstdio>
#include <queue>
#include <cstring>
using namespace std;

//暴力+双向bfs

const int MAXN = 20;
const int INF = 0x3f3f3f3f;

char maze[MAXN][MAXN];
int dist[4][2]={{1,0},{-1,0},{0,1},{0,-1}};
int t, n, m, k;
struct _Node{
    int x, y, time;
    _Node(){
    } 
    _Node(int _x, int _y, int _time){
        x = _x; y = _y; time = _time;
    }
}tmp[110];
int visit[MAXN][MAXN];

void INIT()
{
    for(int i = 0; i < MAXN; ++i)
        for(int j = 0; j < MAXN; ++j) maze[i][j] = '.';
}

bool isOk()
{
    int x,y;
    for(int i=0;i< k;i++)
    {
        x = tmp[i].x; y = tmp[i].y;
        if(!visit[x][y])
            return 0;
    }
    return 1;
}

int bfs(_Node n1, _Node n2)
{
    memset(visit, 0, sizeof(visit));
    queue<_Node> q1;
    queue<_Node> q2;
    q1.push(n1);
    q2.push(n2);
    visit[n1.x][n1.y] = 1; visit[n2.x][n2.y] = 1;

    int ans = 0;
    while(!q1.empty() || !q2.empty()) {
        _Node t1, t2;
        if(!q1.empty()) t1 = q1.front(), q1.pop();
        if(!q2.empty()) t2 = q2.front(), q2.pop();

        if(isOk()) return ans;

        for(int i = 0; i < 4; ++i)
        {
            int dx1 = t1.x + dist[i][0], dy1 = t1.y + dist[i][1];
            int dx2 = t2.x + dist[i][0], dy2 = t2.y + dist[i][1];
            if(maze[dx1][dy1] == '#' && !visit[dx1][dy1])
            {
                q1.push(_Node(dx1, dy1, t1.time + 1));  
                ans = max(ans, t1.time + 1);        
                visit[dx1][dy1] = 1;
            }

            if(maze[dx2][dy2] == '#' && !visit[dx2][dy2])
            {
                q1.push(_Node(dx2, dy2, t2.time + 1));  
                ans = max(ans, t2.time + 1);        
                visit[dx2][dy2] = 1;
            }
        }
    }
    return INF;
}
int main()
{

    scanf("%d", &t);
    for(int cnt = 1; cnt <= t; ++cnt)
    {
        INIT();
        scanf("%d%d", &n, &m);
        int x = 0;
        getchar();
        k = 0;
        for(int i = 1; i <= n; ++i)
        {
            for(int j = 1; j <= m; ++j)
            {
                 scanf("%c", &maze[i][j]);
                 if(maze[i][j] == '#')
                 {
                    tmp[k].x = i;
                     tmp[k].y = j;
                     tmp[k++].time = 0;
                 }
            }
            getchar();
        }

        int ans = INF;

        for(int i = 0; i < k; i++)
        {
            for(int j = i; j < k; j++)
            {
                ans=min(bfs(tmp[i] ,tmp[j]),ans);
            }
        }
        printf("Case %d: %d\n", cnt, ans == INF ? -1 : ans);
    }
    return 0;
}