hdu1520

基本的树形dp

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

const int MAX_N = (int)(6e3) + ;

int n;
int weight[MAX_N];
vector <int> edge[MAX_N];
bool vis[MAX_N];
int dp[MAX_N][];
int root;

void dfs(int father, int u)
{
    for (int i = ; i < (int)edge[u].size(); i++)
    {
        int v = edge[u][i];
        if (v != father)
            dfs(u, v);
    }
    dp[u][] = ;
    dp[u][] = weight[u];
    for (int i = ; i < (int)edge[u].size(); i++)
    {
        int v = edge[u][i];
        if (v == father)
            continue;
        dp[u][] += max(dp[v][], dp[v][]);
        dp[u][] += dp[v][];
    }
}

void input()
{
    for (int i = ; i < n; i++)
    {
        scanf("%d", &weight[i]);
        edge[i].clear();
    }
    memset(vis, , sizeof(vis));
    int a, b;
    while (scanf("%d%d", &a, &b), a | b)
    {
        a--;
        b--;
        vis[a] = true;
        edge[a].push_back(b);
        edge[b].push_back(a);
    }
    for (int i = ; i < n; i++)
    {
        if (!vis[i])
        {
            root = i;
            break;
        }
    }
}

int main()
{
    while (scanf("%d", &n) != EOF)
    {
        input();
        dfs(-, root);
        printf("%d\n", max(dp[root][], dp[root][]));
    }
    return ;
}