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以報酬為標準維護一個大根堆，從根節點往上合併，每次踢掉若干人直到花費合法後更新答案

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 using namespace std;
 5 const int N=100005;
 6 int p[N],noww[2*N],goal[2*N],led[N];
 7 int top[N],dep[N],fth[N],siz[N],son[N][2];
 8 int n,m,t1,cnt; long long ans,val[N],cst[N];
 
 9 void Link(int f,int t)
10 {
11     noww[++cnt]=p[f];
12     goal[cnt]=t,p[f]=cnt;
13 }
14 int Merge(int x,int y)
15 {
16     if(!x||!y) return x+y;
17     if(cst[x]<cst[y]) swap(x,y);
18     int &lson=son[x][0],&rson=son[x][1];
19     rson=Merge(rson,y),fth[rson]=y;
20     if(dep[lson]<dep[rson]) swap(lson,rson);
 
21     dep[x]=dep[rson]+1; return x;
22 }
23 void DFS(int nde)
24 {
25     top[nde]=nde,val[nde]=cst[nde],siz[nde]=1;
26     for(int i=p[nde];i;i=noww[i])
27     {
28         DFS(goal[i]);
29         val[nde]+=val[goal[i]];
30         siz[nde]+=siz[goal[i]];
31         top[nde]=Merge(top[nde],top[goal[i]]);
 
32     }
33     while(val[nde]>m&&siz[nde])
34     {
35         int &tmp=top[nde]; 
36         val[nde]-=cst[tmp],siz[nde]--;
37         top[nde]=Merge(son[tmp][0],son[tmp][1]);
38     }
39     ans=max(ans,1ll*siz[nde]*led[nde]);
40 }
41 int main()
42 {
43     scanf("%d%d",&n,&m);
44     for(int i=1;i<=n;i++)
45     {
46         scanf("%d",&t1); if(t1) Link(t1,i);
47         scanf("%d%d",&cst[i],&led[i]);
48     }
49     DFS(1),printf("%lld",ans);
50     return 0;
51 }