BZOJ 3514 LCT+主席树

思路：

//By SiriusRen
#include <bits/stdc++.h>
using namespace std;
const int N=400500;
int n,m,k,type,ch[N][2],fa[N],minn[N],rev[N],q[N],top,pre[N];
int root[N],tree[N*50],lson[N*50],rson[N*50],cnt,xx,yy,ans;
struct Road{int x,y,wei;}road[N];
bool isroot(int p){return ch[fa[p]][0]!=p&&ch[fa[p]][1]!=p;}
void push_up(int p){
    minn[p]=p;
    if(road[minn[ch[p][0]]].wei<road[minn[p]].wei)minn[p]=minn[ch[p][0]];
    if(road[minn[ch[p][1]]].wei<road[minn[p]].wei)minn[p]=minn[ch[p][1]];
}
void push_down(int p){rev[ch[p][0]]^=1,rev[ch[p][1]]^=1,rev[p]=0,swap(ch[p][0],ch[p][1]);}
void rotate(int p){
    int q=fa[p],y=fa[q],x=(ch[q][1]==p);
    ch[q][x]=ch[p][!x],fa[ch[q][x]]=q;
    ch[p][!x]=q,fa[p]=y;
    if(!isroot(q)){
        if(ch[y][1]==q)ch[y][1]=p;
        if(ch[y][0]==q)ch[y][0]=p;
    }fa[q]=p;push_up(q);
}
void splay(int x){
    q[++top]=x;
    for(int i=x;!isroot(i);i=fa[i])q[++top]=fa[i];
    while(top){if(rev[q[top]])push_down(q[top]);top--;}
    for(int y=fa[x];!isroot(x);rotate(x),y=fa[x])if(!isroot(y)){
        if((ch[y][0]==x)^(ch[fa[y]][0]==y))rotate(x);
        else rotate(y);
    }push_up(x);
}
void access(int x){for(int t=0;x;t=x,x=fa[x])splay(x),ch[x][1]=t,push_up(x);}
void makeroot(int x){access(x),splay(x),rev[x]^=1;}
bool connected(int x,int y){while(fa[x])x=fa[x];while(fa[y])y=fa[y];return x==y;}
void link(int x,int y){makeroot(x),fa[x]=y;}
void split(int x,int y){makeroot(x),access(y),splay(y);}
void cut(int x,int y){split(x,y),ch[y][0]=fa[x]=0;push_up(y);}
void insert(int l,int r,int &pos,int last,int wei){
    pos=++cnt,tree[pos]=tree[last]+1;
    if(l==r)return;
    int mid=(l+r)>>1;
    if(mid<wei)lson[pos]=lson[last],insert(mid+1,r,rson[pos],rson[last],wei);
    else rson[pos]=rson[last],insert(l,mid,lson[pos],lson[last],wei);
}
int query(int l,int r,int pos,int last,int L,int R){
    if(l>=L&&r<=R)return tree[pos]-tree[last];
    int mid=(l+r)>>1;
    if(mid<L)return query(mid+1,r,rson[pos],rson[last],L,R);
    else if(mid>=R)return query(l,mid,lson[pos],lson[last],L,R);
    else return query(l,mid,lson[pos],lson[last],L,R)+query(mid+1,r,rson[pos],rson[last],L,R);
}
int main(){
    scanf("%d%d%d%d",&n,&m,&k,&type);
    for(int i=0;i<=n;i++)road[i].wei=0x3f3f3f3f;
    for(int i=n+1;i<=n+m;i++)scanf("%d%d",&road[i].x,&road[i].y),road[i].wei=i;
    for(int i=n+1;i<=n+m;i++){
        if(connected(road[i].x,road[i].y)){
            if(road[i].x==road[i].y){pre[i-n]=i-n;continue;}
            split(road[i].x,road[i].y);
            int t=minn[road[i].y];
            pre[i-n]=road[t].wei-n;
            cut(road[t].x,t),cut(road[t].y,t);
        }
        link(road[i].x,i),link(road[i].y,i);
    }
    for(int i=1;i<=m;i++)insert(0,m,root[i],root[i-1],pre[i]);
    while(k--){
        scanf("%d%d",&xx,&yy);
        if(type)xx^=ans,yy^=ans;
        printf("%d
",ans=n-query(0,m,root[yy],root[xx-1],0,xx-1));
    }
}