POJ 2486 Apple Tree

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <vector>
 4 #include <cstring>
 5 using namespace std;
 6 const int maxn = 200;
 7 vector<int>g[maxn];
 8 int dp[maxn][maxn][2],w[maxn],n,K;
 9 void dfs(int u,int fa) {
10     for(int i = 0; i <= K; ++i)
11        dp[u][i][0] = dp[u][i][1] = w[u];
12     for(int i = g[u].size()-1; i >= 0; --i) {
13         if(g[u][i] == fa) continue;
14         dfs(g[u][i],u);
15         for(int j = K; j > 0; --j) {
16             for(int k = 1; k <= j; ++k) {
17                 dp[u][j][1] = max(dp[u][j][1],dp[u][j - k][0] + dp[g[u][i]][k - 1][1]);
18                 if(k >= 2) {
19                     dp[u][j][1] = max(dp[u][j][1],dp[u][j-k][1] + dp[g[u][i]][k-2][0]);
20                     dp[u][j][0] = max(dp[u][j][0],dp[u][j - k][0] + dp[g[u][i]][k - 2][0]);
21                 }
22             }
23         }
24     }
25 }
26 int main() {
27     int u,v;
28     while(~scanf("%d%d",&n,&K)) {
29         for(int i = 1; i <= n; ++i) scanf("%d",w+i);
30         for(int i = 0; i < maxn; ++i) g[i].clear();
31         for(int i = 1; i < n; ++i) {
32             scanf("%d%d",&u,&v);
33             g[u].push_back(v);
34             g[v].push_back(u);
35         }
36         memset(dp,0,sizeof dp);
37         dfs(1,-1);
38         printf("%d\n",max(dp[1][K][0],dp[1][K][1]));
39     }
40     return 0;
41 }