1 #include<stdio.h> 2 #include<string.h> 3 4 char a[6][6]; 5 int v[6][6],hash[6][6];//V标记是否已经放过，hash标记是否此位置是否进入过队列 6 int n,sum,max; 7 8 struct N 9 { 10 int x,y; 11 }; 12 13 14 int judge(int x,int y) 15 { 16 int i,j; 17 for(i = x+1; i <= n; i++) 18 if(v[i][y]) return 0; 19 else if(a[i][y] == 'X') break; 20 for(i = x-1; i >= 1; i--) 21 if(v[i][y]) return 0; 22 else if(a[i][y] == 'X') break; 23 for(i = y+1; i <= n; i++) 24 if(v[x][i]) return 0; 25 else if(a[y][i] == 'X') break; 26 for(i = y-1; i >= n; i--) 27 if(v[x][i]) return 0; 28 else if(a[x][i] == 'X') break; 29 return 1; 30 } 31 32 void bfs(int x,int y) 33 { 34 int i,j; 35 sum = 0; 36 struct N q[5000],t1,t; 37 q[0].x = x; 38 q[0].y = y; 39 int s = 0,e = 1; 40 int fx[] = {-1,-1, 1, 1}; 41 int fy[] = { 1,-1,-1, 1}; 42 while(s != e) 43 { 44 t.x = q[s].x; 45 t.y = q[s].y; 46 s++; 47 if(a[t.x][t.y] == '.' && !v[t.x][t.y]) 48 { 49 if(judge(t.x,t.y)) 50 { 51 v[t.x][t.y] = 1; 52 sum++; 53 } 54 } 55 for(i = 0;i < 4; i++) 56 { 57 t1.x = t.x + fx[i]; 58 t1.y = t.y + fy[i]; 59 if(t1.x >= 1 && t1.x <= n && t1.y >= 1 && t1.y <= n && !hash[t1.x][t1.y]) 60 { 61 hash[t1.x][t1.y] = 1; 62 q[e].x = t1.x; 63 q[e].y = t1.y; 64 e++; 65 } 66 } 67 e %= 5000; 68 s %= 5000; 69 } 70 if(max < sum) 71 { 72 73 max = sum; 74 } 75 } 76 77 int main() 78 { 79 int i,j; 80 while(scanf("%d%*c",&n) != EOF && n) 81 { 82 max = 0; 83 for(i = 1;i <= n; i++) 84 scanf("%s",a[i]+1); 85 for(i = 1;i <= n; i++) 86 for(j = 1;j <= n; j++) 87 { 88 memset(v,0,sizeof(v)); 89 memset(hash,0,sizeof(hash)); 90 if(a[i][j] == '.') 91 { 92 bfs(i,j); 93 } 94 } 95 printf("%d\n",max); 96 } 97 return 0; 98 }