UVa 1407 树形背包 Caves

这道题可以和POJ 2486 树形背包DP Apple Tree比较着来做。

参考题解

 #include <iostream>
 #include <cstdio>
 #include <cstring>
 #include <algorithm>
 #include <vector>
 using namespace std;

 const int maxn =  + ;

 int n, Q;
 vector<int> G[maxn], C[maxn];

 int d[maxn][maxn][], cnt[maxn];

 void dfs(int u)
 {
     cnt[u] = ;
     d[u][][] = d[u][][] = ;
     for(int i = ; i < G[u].size(); i++)
     {
         int v = G[u][i];
         int w = C[u][i];
         dfs(v);
         cnt[u] += cnt[v];

         for(int j = cnt[u]; j >= ; j--)
             for(int x = ; x <= j && x <= cnt[v]; x++)
             {
                 d[u][j][] = min(d[u][j][], d[v][x][] + d[u][j-x][] + w * );
                 d[u][j][] = min(d[u][j][], d[v][x][] + d[u][j-x][] + w * );
                 d[u][j][] = min(d[u][j][], d[v][x][] + d[u][j-x][] + w);
             }
     }
 }

 int main()
 {
     int kase = ;
     while(scanf("%d", &n) ==  && n)
     {
         for(int i = ; i < n; i++) { G[i].clear(); C[i].clear(); }
         for(int i = ; i < n; i++)
         {
             int a, b, d; scanf("%d%d%d", &a, &b, &d);
             G[b].push_back(a); C[b].push_back(d);
         }

         memset(d, 0x3f, sizeof(d));
         dfs();

         printf("Case %d:\n", kase++);
         scanf("%d", &Q);
         while(Q--)
         {
             int x; scanf("%d", &x);
             int ans;
             for(ans = n; ans > ; ans--) if(d[][ans][] <= x) break;
             printf("%d\n", ans);
         }
     }

     return ;
 }

代码君