【树形DP】 HDU 1561 The more, The Better

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经典树形DP

#include <cstdio>#include <cstring>#include <cstdlib>#include <string>#include <iostream>#include <algorithm>#include <sstream>#include <cmath>using namespace std;#include <queue>#include <stack>#include <vector>#include <deque>#include <set>#include <map>#include <time.h>;#define cler(arr, val)    memset(arr, val, sizeof(arr))#define FOR(i,a,b)  for(int i=a;i<=b;i++)#define IN   freopen ("in.txt" , "r" , stdin);#define OUT  freopen ("out.txt" , "w" , stdout);typedef long long  LL;const int MAXN = 201;const int MAXM = 201;const int INF = 0x3f3f3f3f;const int mod = 1000000007;struct node{    int v,next;} edge[MAXM];int n,m;int head[MAXM],tol,val[MAXN],dp[MAXN][MAXN];void init(){    cler(val,0);    cler(head,-1);    tol=0;}void addedge(int u,int v){    edge[tol].v=v,edge[tol].next=head[u];    head[u]=tol++;}void dfs(int u){    for(int i=0; i<=m; i++)        dp[u][i]=-INF;    dp[u][1]=val[u];    for(int i=head[u]; ~i; i=edge[i].next)    {        int v=edge[i].v;        dfs(v);        for(int j=m; j>=0; j--)            for( int k=0; k<=j; k++)                dp[u][j]=max(dp[u][j],dp[v][k]+dp[u][j-k]);    }}int main(){#ifndef ONLINE_JUDGE    freopen("in.txt", "r", stdin);#endif    while(~scanf("%d%d",&n,&m),n+m)    {        init();        for(int i=1; i<=n; i++)        {            int a;            scanf("%d %d",&a ,&val[i] );            addedge(a,i);        }        m++;        dfs(0);        printf("%d\n",dp[0][m]);    }}

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