hiho12周树形dp

#include<iostream>
#include<cstdio>
#include<cstring>

using namespace std;

const int maxn = 1111;
int len;
int head[maxn];
//int father[maxn];
struct Node
{
    int to; int next;
}e[maxn * 2];

void add(int from, int to)
{
    e[len].to = to;
    e[len].next = head[from];
    head[from] = len++;
}

int dp[maxn][2222];

/*void build(int root)
{
    for (int i = head[root]; i != -1; i = e[i].next){
        int cc = e[i].to;
        if (cc == father[root]) continue;
        father[cc] = root;
        build(cc);
    }
}*/
int val[maxn];


int dfs(int x, int m,int father)
{
    if (m == 0) return 0;
    for (int i = 1; i <= m; i++)
        dp[x][i] = val[x];
    for (int i = head[x]; i != -1; i = e[i].next){
        int cc = e[i].to;
        if(cc==father) continue;
        dfs(cc, m - 1,x);
        for(int j=m;j>=2;j--){
            int Max = dp[x][j];
            for (int k = j-1;k>=1; k--){
                Max = max(Max, dp[cc][k]+dp[x][j - k]);
            }
            dp[x][j] = Max;
        }
    }
    return dp[x][m];
}


int main()
{

    int n, m;
    int a, b;
    while (cin >> n >> m){
        len = 0;
        memset(dp, 0, sizeof(dp));
//        memset(father, -1, sizeof(father));
        memset(head, -1, sizeof(head));
//        father[1] = 1;
//        build(1);
        for (int i = 1; i <= n; i++)
            scanf("%d", &val[i]);
        for (int i = 0; i < n - 1; i++){
            scanf("%d%d", &a, &b);
            add(a, b); add(b, a);
        }
        cout << dfs(1, m,-1) << endl;
    }
    return 0;
}