/*
dfs，需要注意输入的测试数据的格式。
*/
1 #include <iostream>
2 #include <cstdlib>
3 #include <cstdio>
4 #include <cstddef>
5 #include <iterator>
6 #include <algorithm>
7 #include <string>
8 #include <locale>
9 #include <cmath>
10 #include <vector>
11 #include <cstring>
12 #include <map>
13 #include <utility>
14 #include <queue>
15 #include <stack>
16 #include <set>
17 using namespace std;
18 const int INF = -0x3f3f3f3f;
19 const int MaxN = 55;
20 const int modPrime = 3046721;
21
22 int n;
23 int colorArr[10];
24 char imap[10][10];
25 int answer = 0;
26
27 bool isAdjoinColor(int node, int color)
28 {
29 for (int i = 0; i < n; ++i)
30 {
31 if ((imap[node][i] == '1') && (color == colorArr[i]))
32 {
33 return true;
34 }
35 }
36 return false;
37 }
38
39 void Solve(int nodeNum)
40 {
41 if (nodeNum == n)
42 {
43 ++answer;
44 return;
45 }
46 for (int color = 1; color <= 4; ++color)
47 {
48 if (!isAdjoinColor(nodeNum, color))
49 {
50 colorArr[nodeNum] = color;
51 Solve(nodeNum + 1);
52 colorArr[nodeNum] = -1;
53 }
54 }
55 }
56
57
58 int main()
59 {
60 #ifdef HOME
61 freopen("in", "r", stdin);
62 //freopen("out", "w", stdout);
63 #endif
64
65 fill(colorArr, colorArr + 10, -1);
66 cin >> n;
67 for (int i = 0; i < n; ++i)
68 {
69 for (int j = 0; j < n; ++j)
70 {
71 cin >> imap[i][j];
72 }
73 }
74 Solve(0);
75 cout << answer << endl;
76
77
78 #ifdef HOME
79 cerr << "Time elapsed: " << clock() / CLOCKS_PER_SEC << " ms" << endl;
80 _CrtDumpMemoryLeaks();
81 #endif
82 return 0;
83 }
