HDU1561 The more, The Better

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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 205struct 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;}