BZOJ 2809 Apio2012]dispatching 斜堆 可并堆

#include<cstdio>
#include<vector>
#include<iostream>
#include<algorithm>
#define ll long long
using namespace std;
const int maxn = 200000;
vector<int> f[maxn];
int n,x,tot,rt[maxn],led[maxn];
ll c[maxn],m,ans=0;
struct node
{
int l,r,sz;
ll sum;
}a[maxn];
int merge(int x,int y)
{
if(!x||!y) return x + y;
if(c[x]<c[y]) swap(x,y);
a[x].r=merge(a[x].r,y);
swap(a[x].l,a[x].r); return x;
}
void dfs(int x){
a[x].sum=c[x];a[x].sz=1;rt[x]=x;
for (int i=0;i<f[x].size();i++)
{
int v=f[x][i]; dfs(v);
a[x].sum+=a[v].sum; a[x].sz+=a[v].sz;
rt[x]=merge(rt[x],rt[v]);
}
while(a[x].sum>m)
{
a[x].sum-=c[rt[x]]; a[x].sz--;
rt[x]=merge(a[rt[x]].l,a[rt[x]].r);
}
ans=max(ans,(ll)led[x]*a[x].sz);
}
int main()
{
freopen("dispatching.in","r",stdin);
freopen("dispatching.out","w",stdout);
scanf("%d%lld",&n,&m);
for(int i=1;i<=n;i++)
{
scanf("%d%lld%d",&x,&c[i],&led[i]);
if(x) f[x].push_back(i);
}
dfs(1);
printf("%lld\n",ans);
return 0;
}
/*
5 4
0 3 3
1 3 5
2 2 2
1 2 4
2 3 1
*/