uva 260 - Il Gioco dell'X

题解：

　　一定有人获胜，非黑即白；获胜条件为：black是由 上走到下，white是由 左走到右；

 1 #include <cstdio>
 2 using namespace std;
 3 int N;
 4 char board[201][201];
 5 const int direction[][2] = {{-1,-1},{-1,0},{0,-1},{0,1},{1,0},{1,1}};
 6 void DFS(int i, int j, char c,int &win)
 7 {
 8     board[i][j] = ‘.‘;
 9     if (c == ‘b‘ && i == N-1) win = 1;
10     if (c == ‘w‘ && j == N-1) win = 2;
11     for (int x=0; x<6; ++x){
12         int i_next = i+direction[x][0];
13         int j_next = j+direction[x][1];
14         if (i_next<0 || i_next>=N || j_next<0 || j_next>=N) continue;
15         if (board[i_next][j_next] == c)
16             DFS(i_next, j_next, c, win);
17     }
18 }
19 int main()
20 {
21     //reopen("input.txt","rt",stdin);
22     int Case = 1;
23     while (scanf("%d",&N)){
24         if (!N) break;
25         for (int i=0; i<N; ++i)
26             scanf("%s",board[i]);
27         int win = 0; // win=1:Black  win=2:White
28         for (int i=0; i<N; ++i)
29             if (board[i][0] == ‘w‘)
30                 DFS(i, 0, ‘w‘, win);
31         for (int j=0; j<N; ++j)
32             if (board[0][j] == ‘b‘)
33                 DFS(0, j, ‘b‘, win);
34         if (win == 1) printf("%d B\n",Case++);
35         else printf("%d W\n",Case++);
36     }
37     return 0;
38 }

题解：

　　必有一胜，所以只判断black胜不胜就够了。black胜利的条件是能从第一行走到最后一行，white的胜利条件是能出第一列走到最后一列；

 1 #include <iostream>
 2 using namespace std;
 3
 4 const int maxn = 200 + 10;
 5
 6 char board[maxn][maxn];
 7
 8 void wb(int x, int y, int n, char co)
 9 {
10     if(x>=0 && x<n && y>=0 && y<n)
11         if(board[x][y] == co)
12         {
13             board[x][y] = ‘1‘;
14             wb(x-1, y-1, n, co);
15             wb(x, y-1, n, co);
16             wb(x+1, y, n, co);
17             wb(x-1, y, n, co);
18             wb(x, y+1, n, co);
19             wb(x+1, y+1, n, co);
20         }
21 }
22
23 int main()
24 {
25     int n, i, j, ans = 0;
26     while(cin>>n && n)
27     {
28         for(i = 0; i < n; i++)
29             for(j = 0; j < n; j++)
30                 cin >> board[i][j];
31
32         bool flag = false;
33         //black: first row
34         for(j = 0; j < n; j++)
35             if(board[0][j] == ‘b‘)
36                 wb(0, j, n, ‘b‘);
37         for(j = 0; j < n; j++)
38             if(board[n-1][j] == ‘1‘)
39             {
40                 cout << ++ans << " B" << endl;
41                 flag = true;
42                 break;
43             }
44
45         if(flag)
46             continue;
47         else cout << ++ans << " W" << endl;
48     }
49     return 0;
50 }

uva 260 - Il Gioco dell'X