FZU Problem 2150 Fire Game

#include<iostream>
#include<cstdio>
#include<queue>
#include<cstring>
using namespace std;
#define inf 99999999
char maps[22][22];
int n,m,vis[22][22],go[4][2] = {1,0,-1,0,0,1,0,-1};
struct Pos
{
    int x,y;
};
bool ok(Pos a)
{
    return (a.x>=0 && a.x<n && a.y>=0 && a.y<m && maps[a.x][a.y] == ‘#‘);
}
queue<Pos>que;
int bfs(Pos f1,Pos f2)
{
    while(!que.empty()) que.pop();
    que.push(f1);
    que.push(f2);
    for(int i = 0; i < n; i++)
    {
        for(int j = 0; j < m; j++)
        {
            vis[i][j] = inf;
        }
    }
    vis[f1.x][f1.y] = vis[f2.x][f2.y] = 0;
    while(!que.empty())
    {
        Pos now = que.front();
        que.pop();
        Pos nex;
        for(int i = 0; i < 4; i++)
        {
            nex.x = now.x + go[i][0];
            nex.y = now.y + go[i][1];
            if(ok(nex) && vis[nex.x][nex.y] > vis[now.x][now.y] + 1)
            {
                vis[nex.x][nex.y] = vis[now.x][now.y] + 1;
                que.push(nex);
            }
        }
    }
    int maxv = -999999;
    for(int i = 0; i < n; i++)
    {
        for(int j = 0; j < m; j++)
        {
            if(maps[i][j] == ‘#‘)
            maxv = max(maxv,vis[i][j]);
        }
    }
    return maxv;
}
int main()
{
    int t,ca = 0;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d%d",&n,&m);
        for(int i = 0; i < n; i++)
            scanf("%s",maps[i]);
        int cnt = 0;
        for(int i = 0; i < n; i++)
        {
            for(int j = 0; j < m; j++)
            {
                if(maps[i][j] == ‘#‘)
                    cnt++;
            }
        }
        printf("Case %d: ",++ca);
        if(cnt <= 2)
        {
            printf("%d\n",0);
            continue;
        }
        int ans = inf;
        for(int i = 0; i < n; i++)
        {
            for(int j = 0; j < m; j++)
            {
                if(maps[i][j] == ‘#‘)
                {
                    for(int k = 0; k < n; k++)
                    {
                        for(int q = 0; q < m; q++)
                        {
                            if(j == q && i == k) continue;
                            if(maps[k][q] == ‘#‘)
                            {
                                Pos f1,f2;
                                f1.x = i,f1.y = j;
                                f2.x = k,f2.y = q;
                                ans = min(ans,bfs(f1,f2));
                            }
                        }
                    }
                }
            }
        }
        if(ans == inf)
        {
            cout<<-1<<endl;
        }
        else cout<<ans<<endl;
    }
    return 0;
}