1 #include <stdio.h>
2 #include <iostream>
3 #define MAXN 21
4 using namespace std;
5
6 int _m[MAXN][MAXN];
7 int flag[MAXN];
8
9 int n;
10 int index;
11 int _max;
12 int num;
13 void DFS(int time);
14 int main()
15 {
16 //freopen("acm.acm","r",stdin);
17 //freopen("out.acm","w",stdout);
18 int i;
19 int j;
20 memset(flag,0,sizeof(flag));
21 cin>>n;
22 _max = -1;
23 index = 1;
24 for(i = 0; i < n; ++ i)
25 {
26 for(j = 0; j < n; ++ j)
27 {
28 scanf("%d",&_m[i][j]);
29 }
30 }
31 for(index = 1; index <= n/2+1; ++ index)
32 {
33 num = 0;
34 DFS(0);
35 }
36 cout<<_max<<endl;
37 return 0;
38 }
39
40 void DFS(int time)
41 {
42 if(time == n)
43 return;
44 if(num == index)
45 {
46 int i;
47 int j;
48 int sum = 0;
49 for(i = 0; i < n; ++ i)
50 {
51 for(j = i+1;j < n; ++ j)
52 {
53 if(flag[i] != flag[j])
54 {
55 sum += _m[i][j];
56 }
57 }
58 }
59 if(sum > _max)
60 {
61 _max = sum;
62 }
63 return;
64 }
65 flag[time] = 1;
66 ++ num;
67 DFS(time + 1);
68 -- num;
69 flag[time] = 0;
70 DFS(time + 1);
71 }
