BZOJ3082: Graph2

LCT维护边被删除的时间的最大生成树，删边时若不在MST上则无视。

#include<bits/stdc++.h>
using namespace std;
const int N=250005;
int n,m,q,l1;
struct edge{int u,v,t;}c[N];
struct info{char c;int u,v;}f[N];
struct vec{
	int u,v;
	vec(int u=1e9,int v=0):u(u),v(v){}
};
bool operator<(vec a,vec b){
	return a.u<b.u;
}
struct node;
typedef node*ptr;
struct node{
	ptr i,j,p;
	bool r;
	vec v,s;
	node();
	ptr up(){
		s=min(min(v,i->s),j->s);
		return this;
	}
	void down(){
		if(r)
			i->r^=1,j->r^=1,swap(i,j),r=0;
	}
}e[N];
node::node(){i=j=p=e;}
bool root(ptr o){return o!=o->p->i&&o!=o->p->j;}
void turn(ptr o){
	ptr s=o->p,t=s->p;
	if(!root(s))(s==t->i?t->i:t->j)=o;
	s->p=o,o->p=t;
	if(o==s->i)
		s->i=o->j,o->j->p=s,o->j=s->up();
	else
		s->j=o->i,o->i->p=s,o->i=s->up();
}
void push(ptr o){
	if(!root(o))push(o->p);
	o->down();
}
ptr splay(ptr o){
	push(o);
	while(!root(o)){
		if(!root(o->p))turn(o==o->p->i^o->p==o->p->p->i?o:o->p);
		turn(o);
	}
	return o->up();
}
ptr exp(ptr o){
	ptr s=e;
	while(o!=e)splay(o)->j=s,s=o->up(),o=o->p;
	return s;
}
void link(int i,int j){
	exp(e+i)->r=1,splay(e+i)->p=e+j;
}
void cut(int i,int j){
	ptr s=e+i,t=e+j;
	exp(s)->r=1,exp(t);
	if(s==t->i&&s->j==e)t->i=s->p=e;
	if(t==s->j&&t->i==e)s->j=t->p=e;
}
bool jud(int i,int j){
	exp(e+i)->r=1;
	ptr o=exp(e+j);
	while(o->i!=e)o=o->i,o->down();
	return splay(o)==e+i;
}
void ins(int i){
	if(c[i].u==c[i].v)return;
	int&v=c[i].t;
	if(!v)v=q+1;
	e[n+i].v=vec(v,i);
	if(!jud(c[i].u,c[i].v)){
		link(c[i].u,n+i);
		link(c[i].v,n+i);
	}else{
		int j=e[c[i].u].s.v;
		if(c[i].t>c[j].t){
			cut(c[j].u,n+j);
			cut(c[j].v,n+j);
			link(c[i].u,n+i);
			link(c[i].v,n+i);
		}
	}
}
void del(int i){
	cut(c[i].u,n+i);
	cut(c[i].v,n+i);
}
int main(){
	scanf("%d%d",&n,&m);
	l1=m;
	for(int i=1;i<=m;++i)
		scanf("%d%d",&c[i].u,&c[i].v);
	scanf("%d",&q);
	for(int i=1;i<=q;++i){
		scanf(" %c%d",&f[i].c,&f[i].u);
		if(f[i].c=='D'){
			int&v=c[f[i].u].t;
			if(!v)v=i;
		}else{
			scanf("%d",&f[i].v);
			if(f[i].c=='I')
				c[++l1]=(edge){f[i].u,f[i].v};
		}
	}
	for(int i=1;i<=m;++i)
		ins(i);
	l1=m;
	for(int i=1;i<=q;++i){
		if(f[i].c=='D')del(f[i].u);
		if(f[i].c=='I')ins(++l1);
		if(f[i].c=='Q')
			puts(jud(f[i].u,f[i].v)?"Yes":"No");
	}
}