2N皇后问题

 1 #include <cstdio>
 2 #include <iostream>
 3 using namespace std;
 4 const int maxn = 1000;
 5 int G[maxn][maxn];
 6 int BQ[maxn];
 7 int WQ[maxn];
 8 int n;
 9 int count = 0;
10 void BlackQueue(int k){
11     for(int i = 0; i < k - 1; i++){
12         int judge = BQ[i] - BQ[k-1];
13         if(judge == 0 || judge == k - 1 - i || -judge == k - 1 - i)
14             return;
15     }
16     if(k == n){
17         count++;
18         return;  
19     }
20     for(int i = 0; i < n; i++){
21         if(G[k][i]==1){
22             G[k][i] = 3;
23             BQ[k] = i;
24             BlackQueue(k+1);
25             G[k][i] = 1;
26         }
27     }
28 }
29 void WhiteQueue(int k){
30     for(int i = 0; i < k - 1; i++){
31         int judge = WQ[i] - WQ[k-1];
32         if(judge == 0 || judge == k - 1 - i || -judge == k - 1 - i)
33             return;
34     }
35     if(k == n){
36         BlackQueue(0);
37         return;
38     }
39     for(int i = 0; i < n; i++){
40         if(G[k][i]==1){
41             G[k][i] = 2;
42             WQ[k] = i;
43             WhiteQueue(k+1);
44             G[k][i] = 1;
45         }
46     }
47 } 
48 int main(){
49     cin >> n;
50     for(int i = 0; i < n; i++){
51         for(int j = 0; j < n; j++){
52             scanf("%d", &G[i][j]);
53         }
54     }
55     WhiteQueue(0);
56     cout << count << endl;
57     return 0;
58 }