地址：

题意：找可以到达的黑格子。

mark：dfs..

代码：

#include 
     
      char a[25][25];int sum;void ss(int w, int h, int x, int y){    if(y > 0 && a[x][y-1] == '.')    {        a[x][y-1] = '1';        sum++;        ss(w, h, x, y-1);    }    if(x < h-1 && a[x+1][y] == '.')    {        a[x+1][y] = '1';        sum++;        ss(w, h, x+1, y);    }    if(y < w-1 && a[x][y+1] == '.')    {        a[x][y+1] = '1';        sum++;        ss(w, h, x, y+1);    }    if(x > 0 && a[x-1][y] == '.')    {        a[x-1][y] = '1';        sum++;        ss(w, h, x-1, y);    }    return ;}int main(){    int w,h;    int i,j,f,x,y;    while(scanf("%d%d", &w, &h), w+h)    {        for(i = 0; i < h; i++)            scanf("%s", a[i]);        for(i = f = 0; i < h; i++)        {            if(f) break;            for(j = 0; j < w; j++)                if(a[i][j] == '@') {f = 1, x = i, y = j; break;}        }        a[x][y] = '1';        sum = 1;        ss(w, h, x, y);        printf("%d\n", sum);    }    return 0;}