acdream 1032 树形dp

又是一道树上做分组背包的题目...

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;

const int INF = 999999999;
const int N = 2001;
int value[N];
int head[N];
int dp[N][N];
int cnt[N];
int ans[N];
int n, e;

struct Edge 
{
    int v, next;
} edge[N * 2];

void addEdge( int u, int v )
{
    edge[e].v = v;
    edge[e].next = head[u];
    head[u] = e++;
}

void dfs( int u, int fa )
{
    dp[u][1] = value[u];
    cnt[u] = 1;
    for ( int i = head[u]; i != -1; i = edge[i].next )
    {
        int v = edge[i].v;
        if ( v == fa ) continue;
        dfs( v, u );
        cnt[u] += cnt[v];
    }
    for ( int i = head[u]; i != -1; i = edge[i].next )
    {
        int v = edge[i].v;
        if ( v == fa ) continue;
        for ( int j = cnt[u]; j > 1; j-- )
        {
            for ( int k = 1; k <= cnt[v] && k < j; k++ )
            {
                dp[u][j] = min( dp[u][j], dp[u][j - k] + dp[v][k] );
            }
        }
    }
}

int main ()
{
    while ( scanf("%d", &n) != EOF )
    {
        e = 0;
        memset( head, -1, sizeof(head) );
        for ( int i = 1; i <= n; i++ )
        {
            scanf("%d", value + i);
        }
        for ( int i = 1; i < n; i++ )
        {
            int u, v;
            scanf("%d%d", &u, &v);
            addEdge( u, v );
            addEdge( v, u );
        }
        for ( int i = 1; i <= n; i++ )
        {
            for ( int j = 1; j <= n; j++ )
            {
                dp[i][j] = INF;
            }
        }
        dfs( 1, -1 );
        for ( int i = 1; i <= n; i++ )
        {
            ans[i] = INF;
            for ( int j = 1; j <= n; j++ )
            {
                ans[i] = min( ans[i], dp[j][i] );
            }
            printf("%d", ans[i]);
            if ( i != n ) putchar(' ');
            else putchar('
');     
        }
    }
    return 0;
}