LightOJ 1012(基础图bfs)

我写麻烦了，可以由终点反搜。
基础的bfs，debug了好长时间，平时不多打的原因啊，比赛代码都交给队友，导致我代码能力很弱啊。
警惕警惕！

#include <stdio.h>#include <string.h>#include <algorithm>#include <queue>using namespace std;const int N = 30;char s[N][N];int v[N][N];int dx[4] = {1,-1,0,0};int dy[4] = {0,0,1,-1};struct point{    int x,y;};int n,m;int bfs(int x1,int y1){    memset(v,0,sizeof(v));    queue<point> Q;    point now;    now.x = x1;    now.y = y1;    v[now.x][now.y] = 1;    Q.push(now);    while(!Q.empty())    {        now = Q.front();        //printf("%d %d\n",now.x,now.y);        Q.pop();        for(int i = 0; i < 4; i++)        {            point next;            next.x = now.x+dx[i];            next.y = now.y+dy[i];            //printf("   %d %d   %c  %d\n",next.x,next.y,s[next.x][next.y],v[next.x][next.y]);            if(next.x< 0 || next.x >=m || next.y<0 || next.y>=n)            {                continue;            }            if(s[next.x][next.y] == '@')            {                return 1;            }            if(v[next.x][next.y] == 0 && s[next.x][next.y]=='.')            {                v[next.x][next.y] = 1;                Q.push(next);            }        }    }    return 0;}int main(){    int T,cas = 1;    scanf("%d",&T);    while(T--)    {        memset(v,0,sizeof(v));        scanf("%d %d",&n,&m);        for(int i = 0; i < m; i++)            scanf("%s",s[i]);        int ans = 1;        for(int i = 0; i < m; i++)        {            for(int j = 0; j < n; j++)            {                if(s[i][j] == '.')                {                    if(bfs(i,j))                        ans ++;                }            }        }        printf("Case %d: %d\n",cas++,ans);    }    return 0;}