CSU 1116 Kingdoms（枚举最小生成树）

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<algorithm>
 5 using namespace std;
 6 const int maxn = 20;
 7 int pop[maxn],mat[maxn][maxn];
 8 int T,n,m,k;
 9 
10 int prim(int d,int& ans)
11 {
12     int visit[maxn],f = 1;
13     memset(visit,0,sizeof(visit));
14     d = (d << 1) + 1;
15     for(int i = 1;i <= n;++i)
16     {
17         visit[i] = d & 1;
18         d >>= 1;
19     }
20     int tot = 0;
21     visit[1] = 2;   //等于2才是在集合中的 
22     while(1)
23     {
24         int l = -1,temp = 0x7fffffff;
25         for(int i = 1;i <= n;++i)
26         if(visit[i] == 2)
27         {
28             for(int j = 1;j <= n;++j)
29             if(visit[j] == 1 && mat[i][j] < temp)
30             {
31                 l = j;
32                 temp = mat[i][j];
33             }
34         }
35         if(l == -1 || temp > 100000) break;
36         tot += temp;
37         visit[l] = 2;
38     }
39     ans = 0;
40     for(int i = 1;i <= n;++i)
41     if(visit[i] == 2)
42     ans += pop[i];
43     return tot;
44 }
45 
46 int main()
47 {
48     scanf("%d",&T);
49     while(T--)
50     {
51         scanf("%d%d%d",&n,&m,&k);
52         for(int i = 1;i <= n;++i)
53         scanf("%d",&pop[i]);
54         int x,y,z;
55         memset(mat,0x3f,sizeof(mat));
56         while(m--)
57         {
58             scanf("%d%d%d",&x,&y,&z);
59             mat[x][y] = mat[y][x] = min(mat[x][y],z);
60         }
61         int tot = 0,t;
62         for(int i = 0;i <= (1 << (n-1))-1;++i)
63         {
64             int temp = prim(i,t);
65             if(temp <= k) tot = max(tot,t);
66         }
67         printf("%d\n",tot);
68     }
69     return 0;
70 }