*anniversary party<pku 2342>

  //   树形dp ， 父子兄弟法构建树形结构 ， 状态方程 t[i].vis += t[t[i].child].novis || t[i].novis += t[t[i].child].maxx()
Source Code

Problem: 2342        User: eth1
Memory: 456K        Time: 94MS
Language: C++        Result: Accepted
Source Code
#include <iostream>
#include <algorithm>
using namespace std;
const int M = 6001;
struct node
{
    int father,brother,child;
    int vis,novis;
    int maxx()
    {
        return max(vis,novis);
    }
    void init()
    {
        father=brother=child=novis=0;
    }
}t[M];
void solve(int m)
{
    int tem=t[m].child;
    while(tem)
    {
        solve(tem);
        t[m].vis+=t[tem].novis;
        t[m].novis+=t[tem].maxx();
        tem = t[tem].brother;
    }
}
int main()
{
    int n;
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        t[i].init();
        cin>>t[i].vis;
    }
    int a,b;
    while(cin>>a>>b && a+b)
    {
        t[a].father=b;
        t[a].brother=t[b].child;
        t[b].child=a;
    }
    int i;
    for(i=1;i<=n;i++)
    {
        if(!t[i].father)
        {
            solve(i);
            break;
        }
    }
    int ans=max(t[i].vis,t[i].novis);
    cout<<ans<<endl;
    return 0;
}