洛谷 P2015 二叉苹果树

#include <cstdio>
#include <vector>
#define N 205
using namespace std;
vector<pair<int,int> >G[N];
inline int max(int a,int b) {return a>b?a:b;}
inline int min(int a,int b) {return a>b?b:a;}
int x,y,z,n,q,f[N][N];
int dfs(int now,int pre)
{
    int num=0;
    for(int i=0;i<G[now].size();++i)
    {
        int v=G[now][i].first,val=G[now][i].second;
        if(v==pre) continue;
        num+=dfs(v,now)+1;
        for(int j=min(num,q);j>=1;--j)
         for(int k=j-1;k>=0;--k)
          f[now][j]=max(f[now][j],f[now][j-k-1]+f[v][k]+val);
    }
    return num;
}
int main()
{
    scanf("%d%d",&n,&q);
    for(int i=1;i<n;++i)
    {
        scanf("%d%d%d",&x,&y,&z);
        G[x].push_back(make_pair(y,z));
        G[y].push_back(make_pair(x,z));  
    }
    dfs(1,0);
    printf("%d\n",f[1][q]);
    return 0;
}