[BZOJ3600][线段树][替罪羊树]没有人的算术

#include <cstdio>
#include <iostream>
#include <algorithm>
#define N 600010

using namespace std;

struct lef{
lef *fa,*ch[2],*x,*y;
int sz;
double w;
}pr
,*t,*A
,*rt,*q
,*fix;
int tail;

void clear(){
t=pr;
A[0]=t++;
A[0]->w=0;
}

bool operator <(lef a,lef b){
if(a.x->w==b.x->w) return a.y->w<b.y->w;
return a.x->w<b.x->w;
}

bool operator ==(lef a,lef b){
return a.x->w==b.x->w&&a.y->w==b.y->w;
}

inline lef *born(lef* l,lef* r){
lef *p=t++;
p->x=l; p->y=r;
p->fa=p->ch[0]=p->ch[1]=0;
return p;
}

void dfs(lef *x){
if(!x) return;
dfs(x->ch[0]);
q[++tail]=x;
dfs(x->ch[1]);
}

inline void updat(lef *x){
if(!x) return; x->sz=1;
if(x->ch[0]) x->sz+=x->ch[0]->sz;
if(x->ch[1]) x->sz+=x->ch[1]->sz;
}

lef *build(int l,int r,double x,double y){
if(l>r) return 0;
int mid=l+r>>1;
double md=(x+y)/2.0;
q[mid]->w=md;
q[mid]->ch[0]=build(l,mid-1,x,md);
q[mid]->ch[1]=build(mid+1,r,md,y);
updat(q[mid]); return q[mid];
}

lef *rebuild(lef *x,double l,double r){
tail=0; dfs(x);
return build(1,tail,l,r);
}

inline int max(lef *a,lef *b){
int mx=0;
if(a) mx=max(mx,a->sz);
if(b) mx=max(mx,b->sz);
return mx;
}

lef *InserT(lef *&x,lef *y,double l,double r){
double mid=(l+r)/2.0;
if(!x){y->w=mid;x=y;return y;}
if(*x==*y){y->w=mid;return x;}
lef *p;
if(x->sz++,*y<*x) p=InserT(x->ch[0],y,l,mid);
else p=InserT(x->ch[1],y,mid,r);
if(x->sz*0.75<=max(x->ch[0],x->ch[1])) fix=x;
else if(fix){
if(fix==x->ch[0]) x->ch[0]=rebuild(x->ch[0],l,mid);
else x->ch[1]=rebuild(x->ch[1],mid,r);
fix=0;
}
return p;
}

struct seg{
int l,r,mx;
}T[N<<2];

inline void updat(int x){
if(A[T[x<<1].mx]->w>=A[T[x<<1|1].mx]->w) T[x].mx=T[x<<1].mx;
else T[x].mx=T[x<<1|1].mx;
}

void build(int g,int l,int r){
T[g].l=l; T[g].r=r; T[g].mx=1;
if(l==r){T[g].mx=l;return;}
int mid=l+r>>1;
build(g<<1,l,mid);
build(g<<1|1,mid+1,r);
updat(g);
}

void modify(int g,int x){
if(T[g].l==T[g].r) {T[g].mx=x;return;}
int mid=T[g].r+T[g].l>>1;
if(x<=mid) modify(g<<1,x);
else modify(g<<1|1,x);
updat(g);
}

int query(int g,int l,int r){
if(T[g].l==l&&T[g].r==r) return T[g].mx;
int mid=T[g].l+T[g].r>>1;
if(r<=mid) return query(g<<1,l,r);
if(l>mid) return query(g<<1|1,l,r);
int lq=query(g<<1,l,mid),rq=query(g<<1|1,mid+1,r);
if(A[lq]->w<A[rq]->w) return rq; else return lq;
}

int n,m,x,y,z;
char op;

inline char C(){
static char buf[100000],*p1=buf,*p2=buf;
if(p1==p2){
p2=(p1=buf)+fread(buf,1,100000,stdin);
if(p1==p2) return EOF;
}
return *p1++;
}

inline void reaD(int &x){
char Ch=C();x=0;
for(;Ch>'9'||Ch<'0';Ch=C());
for(;Ch>='0'&&Ch<='9';x=x*10+Ch-'0',Ch=C());
}

int main(){
reaD(n); reaD(m);
clear();
for(int i=1;i<=n;i++)
A[i]=InserT(rt,born(A[0],A[0]),0,1);
build(1,1,n);
for(int i=1;i<=m;i++){
while((op=C())!='C'&&op!='Q');
if(op=='C'){
reaD(x); reaD(y); reaD(z);
A[z]=InserT(rt,born(A[x],A[y]),0,1);
if(fix) rt=rebuild(rt,0,1),fix=0;
modify(1,z);
}
else{
reaD(x); reaD(y);
printf("%d\n",query(1,x,y));
}
}
}