POJ 1321 棋盘问题

 1 #include <iostream>
 2 #include <cstring>
 3 using namespace std;
 4 
 5 const int ROW = 10;
 6 const int COL = 10;
 7 
 8 int book[COL];
 9 char chess[ROW][COL];
10 int step, n;
11 long long  sum;
12 
13 
14 void DFS(char chess[][COL], int row,int k) {    //row代表行数。k代表放置的旗子个数。
15     if (row > n)
16         return;
17     if (k == step) {
18         sum++;
19         return;
20     }
21         
22     for (int j = 1; j <= 2; j++) {
23         if (j == 1)                //代表该行不放置棋子
24             DFS(chess, row + 1, k);   
25         if (j == 2) {              //该行放置棋子
26             for (int i = 0; i < n; i++) {
27                 if (book[i] == 0 && chess[row][i] == ‘#‘) {
28                     book[i] = 1;
29                     DFS(chess, row + 1, k + 1);
30                     book[i] = 0;
31                 }
32             }
33         }
34     }
35 }
36 
37 
38 int main() {
39     while (cin >> n >> step) {
40         sum = 0;
41         cin.get();
42         if (n == -1 && step == -1)
43             break;
44         for (int i = 0; i < n; i++)
45             cin >> chess[i];
46     
47             DFS(chess, 0, 0);
48         
49 
50 
51         cout << sum << endl;
52     }
53 }