题解【luogup1351 NOIp提高组2014 联合权值】

#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cstring>
using namespace std;
#define int long long
const int MAXN = 200200;
const int MOD = 10007;

int n, w[MAXN], cnt, Max = 0, ans, sumw[MAXN], vis1[MAXN], vis2[MAXN], first[MAXN], second[MAXN];
struct edge
{
    int v; edge *next;
}pool[MAXN << 1], *head[MAXN];
inline void addedge(int u, int v)
{
    edge *p = &pool[++cnt], *q = &pool[++cnt];
    p->v = v, p->next = head[u]; head[u] = p;
    q->v = u, q->next = head[v]; head[v] = q;
}
void dfs1(int u)
{
    vis1[u] = 1;
    for(edge *p = head[u]; p; p = p->next)
    {
        sumw[u] += w[p->v];
        if(first[u] < w[p->v]) second[u] = first[u], first[u] = w[p->v];
        else second[u] = max(second[u], w[p->v]);
        if(!vis1[p->v]) dfs1(p->v);
    }
}
void dfs2(int u)
{
    vis2[u] = 1;
    Max = max(Max, first[u] * second[u]);
    for(edge *p = head[u]; p; p = p->next)
    {
        int lh = sumw[u] * w[p->v] - w[p->v] * w[p->v];
        ans = (ans + lh) % MOD;
        if(!vis2[p->v]) dfs2(p->v);
    }
}
#undef int
int main()
{
    memset(second, -1, sizeof(second));
    scanf("%d", &n);
    for(int i = 1; i < n; i++)
    {
        int u, v;
        scanf("%d%d", &u, &v);
        addedge(u, v);
    }
    for(int i = 1; i <= n; i++) scanf("%lld", &w[i]);
    dfs1(1);
    dfs2(1);
    printf("%lld %lld", Max, ans);
    return 0;
}