bzoj3159: 决战 树链剖分+splay

方法很简单，树剖，把区间提取出来，打翻转标记，再放回去。

注意：由于某种原因，我写的是把题目中的r忽略掉的一般情况，否则简单得多。

于是本以为写起来也很简单ovo

结果发现非常繁琐，最后写得又长跑得又慢。

#include<bits/stdc++.h>
#define L(t) (t)->c[0]
#define R(t) (t)->c[1]
#define Z(t) (L(t)->s+1)
#define N 50005
#define M (s+t>>1)
#define u first
#define v second
#define int long long
using namespace std;
struct edge{
	edge* s;
	int v;
}e[N*2],*back(e),*h[N];
void add(int u,int v){
	h[u]=&(*back++
	=(edge){h[u],v});
	h[v]=&(*back++
	=(edge){h[v],u});
}
typedef int ds[N];
ds d,p,num,size,son,top;
void dfs1(int u){
	d[u]=d[p[u]]+1;
	size[u]=1;
	int s=0;
	for(edge* i=h[u];i;i=i->s)
		if(i->v!=p[u]){
			p[i->v]=u;
			dfs1(i->v);
			size[u]+=size[i->v];
			if(s<size[i->v])
				s=size[son[u]=i->v];
		}
}
void dfs2(int u){
	static int tot;
	num[u]=++tot;
	if(size[u]!=1){
		top[son[u]]=top[u];
		dfs2(son[u]);
	}
	for(edge* i=h[u];i;i=i->s)
		if(i->v!=p[u]
		&&i->v!=son[u])
			dfs2(top[i->v]=i->v);
}
struct node{
	int a[3],s,u,v;
	bool rev;
	node *c[2];
}tin[N],*next=tin,
zinc={0,1e9},
*null=&zinc,*root;
int Sum(int u,int v){
	return u+v;
}
int Min(int u,int v){
	return u<v?u:v;
}
int Max(int u,int v){
	return u<v?v:u;
}
int(*f[3])(int,int)
={Sum,Min,Max};
int devolve(node* t){
	if(t==null)
		return 0;
	if(t->rev){
		L(t)->rev^=1;
		R(t)->rev^=1;
		t->rev=0;
		swap(L(t),R(t));
	}
	if(int u=t->u){
		t->u=0;
		L(t)->u+=u;
		R(t)->u+=u;
		t->a[1]+=u;
		t->a[2]+=u;
		t->v+=u;
		t->a[0]+=u*t->s;
	}
	return Z(t);
}
node* update(node* t){
	devolve(L(t));
	devolve(R(t));
	for(int i=0;i!=3;++i)
		t->a[i]=f[i](f[i](
		L(t)->a[i],
		R(t)->a[i]),t->v);
	t->s=R(t)->s+Z(t);
	return t;
}
void link(bool i,
node*& t,node*& s){
	node* d=t->c[i];
	t->c[i]=s;
	s=update(t),t=d;
}
node* splay(int v,
node*& t=root){
	node* d[]={null,null};
	while(v!=devolve(t)){
		bool i=v>Z(t);
		v-=i*Z(t);
		if(v!=devolve(t->c[i])
		&&i==v>Z(t->c[i])){
			v-=i*Z(t->c[i]);
			link(i,t,
			t->c[i]->c[i^1]);
		}
		link(i,t,d[i]);
	}
	for(int i=0;i!=2;++i){
		node* s=t->c[i^1];
		while(d[i]!=null)
			link(i,d[i],s);
		t->c[i^1]=s;
	}
	return update(t);
}
node*& splay(int s,int t){
	splay(s);
	return L(splay(
	t-s+2,R(root)));
}
node* build(int s,int t){
	if(s<=t){
		node* i=next++;
		L(i)=build(s,M-1);
		R(i)=build(M+1,t);
		return update(i);
	}
	return null;
}
typedef pair<int,int> vec;
vec* u=new vec[N];
vec* v=new vec[N];
int solve(int i,int j,
vec*& u,vec*& v){
	vec **s=&u,**t=&v;
	for(;top[i]!=top[j];
	i=p[top[i]]){
		if(d[top[i]]<d[top[j]])
			swap(i,j),
			swap(s,t);
		*(*s)++=vec(
		num[top[i]],num[i]);
	}
	if(d[i]<d[j])
		swap(i,j),
		swap(s,t);
	*(*s)++=vec(num[j],num[i]);
	return num[j];
}
void amend(int p,int q,int j){
	vec *s=u,*t=v;
	solve(p,q,s,t);
	while(s--!=u)
		splay(
		s->u,s->v)->u+=j;
	while(t--!=v)
		splay(
		t->u,t->v)->u+=j;
}
int query(int p,int q,int i){
	int j=i^1?0:1e9;
	vec *s=u,*t=v;
	solve(p,q,s,t);
	while(s--!=u)
		j=f[i](j,splay(
		s->u,s->v)->a[i]);
	while(t--!=v)
		j=f[i](j,splay(
		t->u,t->v)->a[i]);
	return j;
}
void invert(int p,int q){
	int f=0;
	node **x,*j=null,*k=null;
	vec *y,*s=u,*t=v;
	int e=solve(p,q,s,t);
	if(u!=s&&v!=t&&u->u<v->v)
		swap(u,v),
		swap(s,t);
	for(vec* i=u;i!=s;++i)
		if(i->u==e||i->v==e)
			x=&j,y=i;
		else{
			f+=i->v-i->u+1;
			node*& a=splay(
			i->u,i->v);
			R(splay(a->s,a))=j;
			update(j=a),a=null;
		}
	for(vec* i=v;i!=t;++i)
		if(i->u==e||i->v==e)
			x=&k,y=i;
		else{
			node*& a=splay(
			i->u,i->v);
			R(splay(a->s,a))=k;
			update(k=a),a=null;
		}
	if(vec* i=y){
		if(x==&j)
			f+=i->v-i->u+1;
		node*& a=splay(
		i->u,i->v);
		R(splay(a->s,a))=*x;
		update(*x=a),a=null;
	}
	if(!f)k->rev=1;
	else{
		j->rev=1;
		R(splay(j->s,j))=k;
		update(j)->rev=1;
		k=R(splay(f,j));
		R(j)=null;
		update(j)->rev=1;
	}
	if(vec* i=y){
		node*& a=splay(
		i->u,i->u-1);
		*x=R(splay(i->v
		-i->u+1,a=*x));
		R(a)=null,update(a);
	}
	for(vec* i=t-1;i>=v;--i)
		if(i!=y){
			node*& a=splay(
			i->u,i->u-1);
			k=R(splay(i->v
			-i->u+1,a=k));
			R(a)=null,update(a);
		}
	for(vec* i=s-1;i>=u;--i)
		if(i!=y){
			node*& a=splay(
			i->u,i->u-1);
			j=R(splay(i->v
			-i->u+1,a=j));
			R(a)=null,update(a);
		}
}
#undef int
int main(){
	int n,m,s,t,u;
	char a[10];
	scanf("%d%d%*d",&n,&m);
	root=build(0,n+1);
	for(int i=1;i!=n;++i){
		scanf("%d%d",&s,&t);
		add(s,t);
	}
	dfs1(1);
	dfs2(top[1]=1);
	while(m--){
		scanf("%s%d%d",a,&s,&t);
		switch(a[2]){
		case‘v‘:
			invert(s,t);
			break;
		case‘c‘:
			scanf("%d",&u);
			amend(s,t,u);
			break;
		default:
			printf("%lld\n",
			query(s,t,a[2]
			==‘j‘?2:a[2]!=‘m‘));
		}
	}
}