解题：APIO 2012 派遣

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以报酬为标准维护一个大根堆，从根节点往上合并，每次踢掉若干人直到花费合法后更新答案

 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 using namespace std;
 const int N=;
 int p[N],noww[*N],goal[*N],led[N];
 int top[N],dep[N],fth[N],siz[N],son[N][];
 int n,m,t1,cnt; long long ans,val[N],cst[N];
 void Link(int f,int t)
 {
     noww[++cnt]=p[f];
     goal[cnt]=t,p[f]=cnt;
 }
 int Merge(int x,int y)
 {
     if(!x||!y) return x+y;
     if(cst[x]<cst[y]) swap(x,y);
     int &lson=son[x][],&rson=son[x][];
     rson=Merge(rson,y),fth[rson]=y;
     if(dep[lson]<dep[rson]) swap(lson,rson);
     dep[x]=dep[rson]+; return x;
 }
 void DFS(int nde)
 {
     top[nde]=nde,val[nde]=cst[nde],siz[nde]=;
     for(int i=p[nde];i;i=noww[i])
     {
         DFS(goal[i]);
         val[nde]+=val[goal[i]];
         siz[nde]+=siz[goal[i]];
         top[nde]=Merge(top[nde],top[goal[i]]);
     }
     while(val[nde]>m&&siz[nde])
     {
         int &tmp=top[nde];
         val[nde]-=cst[tmp],siz[nde]--;
         top[nde]=Merge(son[tmp][],son[tmp][]);
     }
     ans=max(ans,1ll*siz[nde]*led[nde]);
 }
 int main()
 {
     scanf("%d%d",&n,&m);
     for(int i=;i<=n;i++)
     {
         scanf("%d",&t1); if(t1) Link(t1,i);
         scanf("%d%d",&cst[i],&led[i]);
     }
     DFS(),printf("%lld",ans);
     return ;
 }