【BZOJ3514】Codechef MARCH14 GERALD07加强版 LCT+主席树

题解：

还是比较简单的

首先我们的思路是 确定起点 然后之后贪心的选择边（也就是越靠前越希望选）

我们发现我们只需要将起点从后向前枚举

然后用lct维护连通性

因为强制在线，所以用主席树记录状态就可以了

*数组开小查了很久

代码：

#include <bits/stdc++.h>
using namespace std;
#define IL inline
#define rint register int 
#define rep(i,h,t) for (rint i=h;i<=t;i++)
#define dep(i,t,h) for (rint i=t;i>=h;i--)
const int INF=1e9;
const int N=4e5+10;
char ss[1<<24],*A=ss,*B=ss;
IL char gc()
{
  return A==B&&(B=(A=ss)+fread(ss,1,1<<24,stdin),A==B)?EOF:*A++; 
}
template<class T> void read(T &x)
{
  rint f=1,c; while (c=gc(),c<48||c>57) if (c=='-') f=-1; x=c^48;
  while (c=gc(),47<c&&c<58) x=(x<<3)+(x<<1)+(c^48); x*=f;
}
int data[N],ls[N],rs[N],fa[N],v[N];
bool rev[N];
IL void updata(int x)
{
  data[x]=min(min(data[ls[x]],data[rs[x]]),v[x]);
}
IL void down(int x)
{
  if (!rev[x]) return;
  rev[ls[x]]^=1; rev[rs[x]]^=1;
  swap(ls[x],rs[x]);
  rev[x]=0;
}
IL bool pd(int x)
{
  int fa1=fa[x];
  if (ls[fa1]!=x&&rs[fa1]!=x) return(0);
  else return(1);
}
void rotate(int x,int y)
{
  int fa1=fa[x];
  if (y==1)
  {
    rs[fa1]=ls[x];
    if (ls[x]) fa[ls[x]]=fa1;
  } else
  {
    ls[fa1]=rs[x];
    if (rs[x]) fa[rs[x]]=fa1;
  }
  fa[x]=fa[fa1];
  if (pd(fa1))
  {
    if (ls[fa[fa1]]==fa1) ls[fa[fa1]]=x; else rs[fa[fa1]]=x;
  }
  fa[fa1]=x;
  if (y==1) ls[x]=fa1; else rs[x]=fa1;
  updata(fa1); updata(x);
}
void dfs(int x)
{
  if (pd(x)) dfs(fa[x]);
  down(x);
}
void splay(int x)
{
  dfs(x);
  int fa1=fa[x];
  while (pd(x))
  {
    if (!pd(fa1))
    {
      if (x==ls[fa1]) rotate(x,2); else rotate(x,1);
    } else
    if (ls[fa[fa1]]==fa1)
      if (ls[fa1]==x)
        rotate(fa1,2),rotate(x,2);
      else 
        rotate(x,1),rotate(x,2);
    else
      if (rs[fa1]==x)
        rotate(fa1,1),rotate(x,1);
      else 
        rotate(x,2),rotate(x,1);
    fa1=fa[x];
  }
}
void access(int x)
{
  for (int y=0;x;y=x,x=fa[x])
  {
    splay(x); rs[x]=y; updata(x);
  }
}
int fdr(int x)
{
  access(x);
  splay(x);
  while (ls[x]) x=ls[x];
  return(x); 
}
void mkr(int x)
{
  access(x);
  splay(x);
  rev[x]^=1;
}
void split(int x,int y)
{
  mkr(x);
  access(y);
  splay(y);
}
void link(int x,int y)
{
  mkr(x);
  access(y);
  splay(y);
  fa[x]=y;
}
void cut(int x,int y)
{
  mkr(x);
  access(y);
  splay(y);
  ls[y]=fa[x]=0;
  updata(y);
}
#define mid ((h+t)/2)
int root[N],jl1[N],jl2[N];
struct segtment{
  int p[N*20],ls[N*20],rs[N*20],cnt;
  segtment() { cnt=0; }
  void updata(int x)
  {
    p[x]=p[ls[x]]+p[rs[x]];
  }
  void change(int last,int &x,int h,int t,int pos,int k)
  {
    x=++cnt; ls[x]=ls[last]; rs[x]=rs[last];
    p[x]=p[last]+k;
    if (h==t) return;
    if (pos<=mid) change(ls[last],ls[x],h,mid,pos,k);
    else change(rs[last],rs[x],mid+1,t,pos,k);
    updata(x);
  }
  int query(int x,int h,int t,int h1,int t1)
  {
    if (h1<=h&&t<=t1) return(p[x]);
    int ans=0;
    if (h1<=mid) ans+=query(ls[x],h,mid,h1,t1);
    if (mid<t1) ans+=query(rs[x],mid+1,t,h1,t1);
    return(ans);
  }
}S;
int n,m,k,type;
int main()
{
  freopen("1.in","r",stdin);
  freopen("1.out","w",stdout);
  read(n); read(m); read(k); read(type);
  int ans=0;
  data[0]=v[0]=INF;
  rep(i,1,n) v[i]=INF,v[i+n]=i;
  rep(i,1,m)v[i+n]=i;
  int p=0,maxn=0;
  rep(i,1,m)
  {
   // cout<<i<<endl;
    int x,y;
    root[i]=root[i-1];
    read(x); read(y);
    if (x==y) continue; 
    jl1[i]=x;jl2[i]=y;
    mkr(y);
    if (fdr(x)==y)
    {
      split(x,y);
      int x1=data[y];
      cut(x1+n,jl1[x1]);
      cut(x1+n,jl2[x1]);
      S.change(root[i],root[i],1,m,x1,-1);
      p--;
    }
    p++; 
    link(i+n,x);
    link(i+n,y);
    S.change(root[i],root[i],1,m,i,1);
    if (p>n) return 0;
    maxn=max(maxn,p);
  }
  rep(i,1,k)
  {
    int x,y;
    read(x); read(y);
    if (type) x^=ans,y^=ans;
    printf("%d
",ans=n-S.query(root[y],1,m,x,y));
  }
  return 0;
}