HDU1561 The more, The Better

http://acm.hdu.edu.cn/showproblem.php?pid=1561

 树形DP+01背包

#include <cstdio>
#include <cstring>
#include <cmath>
#include <map>
#include <set>
#include <vector>
#include <iostream>
#include <algorithm>
#include <queue>
using namespace std;
const double eps=1e-8;
const double INF=1e50;
//const double pi=acos(-1);

#define N 205

struct point
{
    int v;
    vector<int> a;
}p[N];

int f[N][N],n,m;
bool vis[N];

void ser(int x)
{
    vis[x]=false;
    int i,j,k,t;

    for (i=0;i<p[x].a.size();i++)
    {
        t=p[x].a[i];
        if (vis[t])
        {
            ser(t);

            for (k=m+1;k>=2;k--)
            for (j=1;j<k;j++)
            if (f[x][k-j]+f[t][j]>f[x][k])
            f[x][k]=f[t][j]+f[x][k-j];
        }
    }
}

int main()
{
    freopen("a","r",stdin);

    int i,j,k;
    while (scanf("%d%d",&n,&m))
    {
        if (n==0 && m==0) break;
        for (i=0;i<=n;i++) p[i].a.clear();

        int q;
        memset(f,0,sizeof(f));
        memset(vis,true,sizeof(vis));
        for (i=1;i<=n;i++)
        {
            scanf("%d%d",&q,&p[i].v);
            p[q].a.push_back(i);
            f[i][1]=p[i].v;
        }

        vis[0]=false;
        ser(0);

        printf("%d\n",f[0][m+1]);
    }

    return 0;
}