[堆 折线] UOJ#205 & BZOJ4585 【APIO2016】Fireworks

大概是一个子树中的 fx 是一个单峰函数，转折点用可并堆维护

具体看这里

#include 
#include 
#include 

using namespace std;

typedef long long ll;

const int N=1200010;

int n,m,cnt,fa[N],G[N];
struct edge{
  int t,w,nx;
}E[N];

inline char nc(){
  static char buf[100000],*p1=buf,*p2=buf;
  return p1==p2&&(p2=(p1=buf)+fread(buf,1,100000,stdin),p1==p2)?EOF:*p1++;
}

inline void read(int &x){
  char c=nc(); x=0;
  for(;c>'9'||c<'0';c=nc());for(;c>='0'&&c<='9';x=x*10+c-'0',c=nc());
}

inline void addedge(int x,int y,int w){
  E[++cnt].t=y; E[cnt].nx=G[x]; G[x]=cnt; E[cnt].w=w;
}

struct node{
  node *l,*r;
  ll v;
}p[N],*rt[N],*t;

inline int ran(){
  static int x=31253125; x+=(x<<4)+1; return x&65536;
}

inline node *New(ll x){
  t->v=x; t->l=t->r=0;
  return t++;
}

node *Merge(node *x,node *y){
  if(!x || !y) return !x?y:x;
  if(x->vv) swap(x,y);
  ran()?x->l=Merge(x->l,y):x->r=Merge(x->r,y);
  return x;
}

inline void Pop(int v){
  rt[v]=Merge(rt[v]->l,rt[v]->r);
}

ll ans;

int main(){
  freopen("1.in","r",stdin);
  freopen("1.out","w",stdout);
  read(n); read(m); t=p;
  for(int i=2,p,w;i<=n+m;i++)
    read(p),read(w),addedge(p,i,w),ans+=w;
  for(int i=n+1;i<=n+m;i++)
    rt[i]=Merge(rt[i],Merge(New(0),New(0)));
  for(int x=n;x;x--){
    int d=0;
    for(int i=G[x];i;i=E[i].nx){
      int v=E[i].t; ll L,R;
      R=rt[v]->v; Pop(v);
      L=rt[v]->v,Pop(v);
      rt[v]=Merge(rt[v],New(L+E[i].w));
      rt[v]=Merge(rt[v],New(R+E[i].w));
      rt[x]=Merge(rt[x],rt[v]);
      d++;
    }
    for(int i=1;i1);
  while(rt[1]) ans-=rt[1]->v,Pop(1);
  cout<return 0;
}