BNUOJ 13358 Binary Apple Tree

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <climits>
 7 #include <vector>
 8 #include <queue>
 9 #include <cstdlib>
10 #include <string>
11 #include <set>
12 #include <stack>
13 #define LL long long
14 #define pii pair<int,int>
15 #define INF 0x3f3f3f3f
16 using namespace std;
17 struct arc {
18     int to,w;
19     arc(int x = 0,int y = 0):to(x),w(y) {}
20 };
21 vector<arc>g[110];
22 int n,m,dp[110][110],cnt[110];
23 void dfs(int u,int fa) {
24     cnt[u] = 1;
25     for(int i = 0; i < g[u].size(); i++) {
26         if(g[u][i].to == fa) continue;
27         dfs(g[u][i].to,u);
28         cnt[u] += cnt[g[u][i].to];
29     }
30     for(int i = 0; i < g[u].size(); i++) {
31         if(g[u][i].to == fa) continue;
32         for(int j = cnt[u]; j > 0; j--) {
33             for(int k = 1; k <= cnt[g[u][i].to] && k < j; k++) {
34                 dp[u][j] = max(dp[u][j],dp[u][j-k]+dp[g[u][i].to][k]+g[u][i].w);
35             }
36         }
37     }
38 }
39 int main() {
40     int i,u,v,w;
41     while(~scanf("%d %d",&n,&m)) {
42         for(i = 0; i <= n; i++)
43             g[i].clear();
44         for(i = 1; i < n; i++) {
45             scanf("%d %d %d",&u,&v,&w);
46             g[u].push_back(arc(v,w));
47             g[v].push_back(arc(u,w));
48         }
49         memset(dp,0,sizeof(dp));
50         dfs(1,-1);
51         printf("%d\n",dp[1][m+1]);
52     }
53     return 0;
54 }