（树形DP）tree of tree (zju)

#include<cstdio>
#include<iostream>
#include<cstring>
#include<queue>
#include<string>
#include<vector>
#include<cmath>
#include<algorithm>

using namespace std;

const int N = 100;
int n,m;
vector<int> v
;
long long dp

,num
,w
;

void dfs(int cur,int pre)
{
//cout<<cur<<' '<<pre<<endl;
for (int i=2;i<=m;i++) dp[cur][i]=0;
dp[cur][1]=w[cur];
for (int i=0,len=v[cur].size();i<len;i++) if (v[cur][i]!=pre)
{
int son=v[cur][i];
//cout<<son<<endl;
dfs(son,cur);
for (int j=m-1;j;j--)
{
for (int k=j+1;k<=m;k++)
{
if (dp[son][k-j] == 0) break;
dp[cur][k]=max(dp[cur][k],dp[cur][j]+dp[son][k-j]);
}
}
}
}

int main()
{
freopen("in","r",stdin);
while (cin>>n>>m)
{
//	cout<<n<<' '<<m<<endl;
for (int i=0;i<n;i++)
{
scanf("%lld",w+i);
v[i].clear();
num[i]=0;
}
for (int i=1;i<n;i++)
{
int a,b;
scanf("%d%d",&a,&b);
v[a].push_back(b);
v[b].push_back(a);
}
dfs(0,-1);

long long  ans=0;
for (int i=0;i<n;i++) ans=max(ans,dp[i][m]);
printf("%lld\n",ans);

}

}