题目
P5385 [Cnoi2019]须臾幻境
做法
考虑一条边\((u,v)\)是否\([L,R]\)中的贡献：\([L,R]\)中第一条位于\(u,v\)链的边，则减少了一个联通块
实现：\(LCT\)维护最小边，产生环则删除最小边，再替换\((\)和这题差不多\()\)
得出删除序列，建好主席树，直接查询\([L,R]\)中小于\(L\)的数量即可
Code
#include
typedef int LL;
inline LL Read(){
LL x(0),f(1); char c=getchar();
while(c<'0' || c>'9'){
if(c=='-') f=-1; c=getchar();
}
while(c>='0' && c<='9'){
x=(x<<3)+(x<<1)+c-'0'; c=getchar();
}return x*f;
}
const LL maxn=1e6+9,inf=0x3f3f3f3f;
LL n,m,q,seed;
LL ear[maxn];
namespace LCT{
struct node{
LL u,v;
}e[maxn];
LL son[maxn][2],fa[maxn],mi[maxn],mi_n[maxn],val[maxn],sta[maxn],r[maxn];
inline LL Notroot(LL x){
return son[fa[x]][0]==x || son[fa[x]][1]==x;
}
inline void Update(LL x){
LL lt(son[x][0]),rt(son[x][1]);
mi[x]=std::min(mi[lt],mi[rt]);
if(mi[x]==mi[lt]){
mi_n[x]=mi_n[lt];
}else{
mi_n[x]=mi_n[rt];
}
if(val[x]<=mi[x]){
mi[x]=val[x]; mi_n[x]=x;
}
}
inline void Pushr(LL x){
std::swap(son[x][0],son[x][1]); r[x]^=1;
}
inline void Pushdown(LL x){
if(r[x]){
if(son[x][0]) Pushr(son[x][0]);
if(son[x][1]) Pushr(son[x][1]);
r[x]=0;
}
}
inline void Rotate(LL x){
LL y(fa[x]),z(fa[y]),lz(son[y][1]==x);
if(Notroot(y)) son[z][son[z][1]==y]=x;
son[y][lz]=son[x][lz^1]; fa[son[y][lz]]=y;
son[x][lz^1]=y; fa[y]=x;fa[x]=z;
Update(y); Update(x);
}
inline void Splay(LL x){
LL y(x),tot(0);
sta[++tot]=y;
while(Notroot(y)) sta[++tot]=y=fa[y];
while(tot) Pushdown(sta[tot--]);
while(Notroot(x)){
y=fa[x];
if(Notroot(y)){
LL z(fa[y]);
if((son[y][0]==x)^(son[z][0]==y)) Rotate(x); else Rotate(y);
}Rotate(x);
}
}
inline void Access(LL x){
for(LL y=0;x;y=x,x=fa[x]){
Splay(x); son[x][1]=y; Update(x);
}
}
inline void Makeroot(LL x){
Access(x); Splay(x); Pushr(x);
}
inline void Split(LL x,LL y){
Makeroot(x); Access(y); Splay(y);
}
inline LL Query(LL x,LL y){
Split(x,y); return mi_n[y];
}
inline LL Find(LL x){
Access(x); Splay(x);
while(son[x][0]){
Pushdown(x); x=son[x][0];
}Splay(x);
return x;
}
inline void Cut(LL x,LL y){
Split(x,y); son[y][0]=fa[x]=0; Update(y);//这里也可不更新，因为在查询时整条链都会更新
}
inline void Link(LL x,LL y){
Makeroot(x); fa[x]=y;
}
inline void Solve(){
for(LL i=0;i<=n;++i) val[i]=mi[i]=inf,mi_n[i]=i;
LL tot=n;
for(LL i=1;i<=m;++i){
LL u(Read()),v(Read());
e[i]=(node){u,v};
if(u==v){
ear[i]=i; continue;
}else if(Find(u)==Find(v)){
LL t(Query(u,v)),x(val[t]); ear[i]=x;
Cut(e[x].u,t); Cut(e[x].v,t);
}
++tot; mi[tot]=val[tot]=i; mi_n[tot]=tot;
Link(u,tot); Link(v,tot);
}
}
}
namespace Sgt{
LL nod;
LL size[maxn*20],son[maxn*20][2],root[maxn];
void Update(LL pre,LL &now,LL l,LL r,LL v){
now=++nod; size[now]=size[pre]+1;
if(l==r) return;
LL mid(l+r>>1);
if(v<=mid){
Update(son[pre][0],son[now][0],l,mid,v);
son[now][1]=son[pre][1];
}else{
Update(son[pre][1],son[now][1],mid+1,r,v);
son[now][0]=son[pre][0];
}
}
LL Query(LL pre,LL now,LL l,LL r,LL v){
if(l==r) return size[now]-size[pre];
LL mid(l+r>>1);
if(mid0)
l=1ll*(l+1ll*seed*lst%m)%m+1,
r=1ll*(r+1ll*seed*lst%m)%m+1;
if(l>r) std::swap(l,r);
printf("%d\n",lst=n-Query(root[l-1],root[r],0,m,l-1));
}
}
}
int main(){
n=Read(); m=Read(); q=Read(); seed=Read();
LCT::Solve();
Sgt::Solve();
return 0;
}