前言
动点分。难度属于套路难度,只要掌握了模板,就会做。所以没有详细说明。
题面
戳;
sol
提醒的是,该题不需要建立tofa堆
代码
#include<bits/stdc++.h>
using namespace std;
const int _ = 1e5+1e3,INF = 2e9;
inline char gc(){
static char buf[1<<6],*p1=buf,*p2=buf;
return (p1==p2)&&(p2=(p1=buf)+fread(buf,1,1<<6,stdin),p1==p2)?EOF:*p1++;
}
template <class T>
inline void read(T&data){
data=0;
register char ch=0;
while(ch<'0'||ch>'9')ch=gc();
while(ch<='9'&&ch>='0'){
data=(data<<3)+(data<<1)+(ch&15);
ch=gc();
}
return;
}
namespace stringio{char Getchar(){register char ch=0;while(ch<'A'||ch>'Z')ch=gc();return ch;}}
using namespace stringio;
int n,m;
bool used[_];//零表示灭
struct heap{
priority_queue<int,vector<int>,greater<int> >Q,del;
void Delete(register int x){del.push(x);return;}
void Push(register int x){Q.push(x);return;}
void Clear(){while(!del.empty()&&del.top()==Q.top())Q.pop(),del.pop();return;}
int Size(){Clear();return Q.size()-del.size();}
int Get_fir(){Clear();if(Q.empty())return -1;else return Q.top();}
int Get_sec(){
if(Size()<2)return -1;
register int x1 = Get_fir();Q.pop();
register int x2 = Get_fir();Q.push(x1);
return x2;
}
bool Empty(){Clear();return Q.empty();}
int Get(){
if(Size()<2)return -1;
register int x1 = Get_fir(),x2 = Get_sec();
return (x2 + x1);
}
}c[_],b[_];
namespace Tree{
int head[_],cnt,par[_],root;
struct edge{
int nt,to;
}e[_];
void add(register int a,register int b){e[++cnt].to=b,e[cnt].nt=head[a],head[a]=cnt;par[b]=a;return;}
}
class orginal_tree{
private:
int head[_];
struct edge{
int nt,to;
}e[_<<1];
bool vis[_];
int size[_],MX,all,lg[_<<1],st[18][_<<1],cnt,dfn[_],dis[_],fdfn[_],app[_],tot,root;
void dfs(int now,int fa){
dfn[now]=++cnt,fdfn[cnt]=now;st[0][++tot]=cnt,app[now]=tot;
for(register int i=head[now];i;i=e[i].nt){
if(e[i].to==fa)continue;
dis[e[i].to]=dis[now]+1;
dfs(e[i].to,now);
st[0][++tot]=dfn[now];
}
}
int get_lca(register int u,register int v){
u=app[u],v=app[v];
if(u<v)swap(u,v);register int LEN=lg[u-v+1];
return fdfn[min(st[LEN][v],st[LEN][u+1-(1<<LEN)])];
}
void getroot(register int now,register int fa){
size[now]=1;
int mx=0;
for(register int i=head[now];i;i=e[i].nt)
{
if(vis[e[i].to]||e[i].to==fa)continue;
getroot(e[i].to,now);
size[now]+=size[e[i].to];
mx=mx<size[e[i].to]?size[e[i].to]:mx;
}
mx=mx<all-size[now]?all-size[now]:mx;
if(MX>mx)MX=mx,root=now;
}
void p_divide(int now){
vis[now]=1;
for(register int i=head[now];i;i=e[i].nt){
if(vis[e[i].to])continue;
MX=INF,all=size[e[i].to];
getroot(e[i].to,0);
Tree::add(now,root);
p_divide(root);
}
}
public:
void add(register int a,register int b){e[++cnt].to=a,e[cnt].nt=head[b],head[b]=cnt;}
void Add(){for(register int i=1,a,b;i<n;++i)read(a),read(b),add(a,b),add(b,a);}
void init(){
Add();
MX=INF,all=n;
cnt=0;dfs(1,0);getroot(1,0);
register int us=2*n-1;
for(register int i=2;i<=us;++i)lg[i]=lg[i>>1]+1;
for(register int j=1;j<=17;++j)
for(register int i=1;i<=us&&(i+(1<<(j-1)))<=us;++i)
st[j][i]=min(st[j-1][i],st[j-1][i+(1<<(j-1))]);
Tree::root=root;
p_divide(root);
}
int getdist(register int u,register int v){
return dis[u]+dis[v]-2*dis[get_lca(u,v)];
}
}tr;
namespace Tree{
void insert(register int now){
used[now]=1;
c[now].Push(0);
for(register int i=par[now];i;i=par[i]){
c[i].Push(tr.getdist(now,i));
}
}
void erase(register int now){
used[now]=0;
c[now].Delete(0);
for(register int i=par[now];i;i=par[i]){
c[i].Delete(tr.getdist(now,i));
}
}
void init(){
for(register int i=1;i<=n;++i)
insert(i) ;
}
int query(register int now){
register int MMMXX=2e9;
for(register int i=now;i;i=par[i]){
register int ddd=tr.getdist(i,now);
register int ans=c[i].Get_fir();
if(ans==-1)continue;
else MMMXX=min(MMMXX,ans+ddd);
}
if(MMMXX==2e9)return -1;
return MMMXX;
}
}
int main(){
read(n);
tr.init();
//Tree::init();
read(m);
while(m--){
register int ki;read(ki);
register int fdfdf;read(fdfdf);
if(ki==1){
printf("%d\n",Tree::query(fdfdf));
}
else {
used[fdfdf]?Tree::erase(fdfdf):Tree::insert(fdfdf);
}
}
}