hdu2489 Minimal Ratio Tree dfs枚举组合情况+最小生成树

 #include <stdio.h>
 #include <set>
 #include <string.h>
 #include <algorithm>
 using namespace std;

 const int maxn = ;
 const int inf = ;
 double minans;
 int vis[maxn];//记录选中的点
 int mp[maxn][maxn], ans[maxn][maxn];
 int min_road[maxn];

 int Prim(int n)
 {
     int i, j, min_i, minm, sum = ;
     int dis[maxn];
     int vis[maxn];
     for (i = ; i <= n; i++)
         dis[i] = ans[i][];
     memset(vis, false, sizeof vis);
     vis[] = true;
     for (i = ; i<n; i++)
     {
         minm = inf, min_i = i;
         for (j = ; j <= n; j++)
         {
             if (vis[j] == false && dis[j]<minm)
             {
                 minm = dis[j];
                 min_i = j;
             }
         }
         if (minm == inf)
             break;
         sum += minm;
         vis[min_i] = true;
         for (j = ; j <= n; j++)
         {
             if (vis[j] ==  && dis[j]>ans[min_i][j])
                 dis[j] = ans[min_i][j];
         }
     }
     return sum;
 }

 int ok(int n)
 {
     memset(vis, , sizeof vis);
     int cnt = ;
     int m = n, cont = ;
     while (m)
     {
         if (m % )
             vis[cont++] = cnt;
         cnt++;
         m /= ;
     }
     return cont;
 }

 int main()
 {
     int d[maxn], maxm;
     int n, i, j, k, cnt, m;
     while (scanf("%d%d", &n, &m) != EOF)
     {
         if (n ==  && m == )
             break;
         maxm = ;
         for (i = ; i <= n; i++)
             maxm *= ;
         for (i = ; i <= n; i++)
             scanf("%d", &d[i]);
         for (i = ; i <= n; i++)
         {
             for (j = ; j <= n; j++)
             {
                 scanf("%d", &mp[i][j]);
             }
         }
         minans = 9999999999.0;
         int sum_point;
         for (i = ; i < maxm; i++)
         {
             if (ok(i) == m + )
             {
                 sum_point = ;
                 for (j = ; j <= m; j++)
                 {
                     sum_point += d[vis[j]];//选的点
                     for (k = j + ; k <= m; k++)
                     {
                         ans[j][k] = ans[k][j] = mp[vis[j]][vis[k]];
                     }
                 }
                 int sum = Prim(m);
                 if ((sum*1.0 / sum_point) < minans)
                 {
                     minans = sum*1.0 / sum_point;
                     for (i = ; i <= m; i++)
                         min_road[i] = vis[i];
                 }
             }
         }
         for (i = ; i <= m - ; i++)
             printf("%d ", min_road[i]);
         printf("%d\n", min_road[i]);
     }
     return ;
 }