替罪羊树套Trie，Trie合并用线段树合并，注意常数优化。
顺便AC800题纪念~~~
#include<cstdio>
#include<cmath>
#include<algorithm>
using namespace std;
const int N=200010,inf=19,M=32000010;
struct info{
int v1,v2;
info(){v1=v2=0;}
info(int _v1,int _v2){v1=_v1,v2=_v2;}
}maxv;
inline info merge(info a,info b){
if(b.v1>a.v1){
a.v2=b.v2>a.v1?b.v2:a.v1;
a.v1=b.v1;
}else if(b.v1>a.v2)a.v2=b.v1;
return a;
}
struct node{int l,r,v;node(){}node(int _l,int _r,int _v){l=_l,r=_r,v=_v;}}T[M];
int rub,getn[M];
const double A=0.8;
int size[N],real[N],ex[N],son[N][2],val[N],f[N],tot,root,id[N],cnt;
info mv[N];
int h[N],pool[N];
int ans,cntpool,cntone,one[N];
int n,q,x,y,i,Pow[20],Inv[20];char ch;
//Trie begin
inline void Max(int&a,int b){if(a<b)a=b;}
inline int Newtrienode(int l,int r,int v){
int x=getn[rub--];
T[x]=node(l,r,v);
return x;
}
void Ins(int&x,int a,int c,int p){
if(!x)x=Newtrienode(0,0,0);
T[x].v+=p;
if(~a)Ins(c&Pow[a]?T[x].r:T[x].l,a-1,c,p);
}
int Merge(int x,int y){
if(!x&&!y)return 0;
return Newtrienode(Merge(T[x].l,T[y].l),Merge(T[x].r,T[y].r),T[x].v+T[y].v);
}
inline int Ask(int x,int c){
int t=1048575,a;
for(a=inf;t>ans&&~a;a--)if(c&Pow[a]){
if(T[T[x].l].v)x=T[x].l;else t&=Inv[a],x=T[x].r;
}else{
if(T[T[x].r].v)x=T[x].r;else t&=Inv[a],x=T[x].l;
}
return t;
}
inline void Ask(int c){
int i;
for(i=1;i<=cntone;i++)Max(ans,one[i]^c);
for(i=1;i<=cntpool;i++)Max(ans,Ask(pool[i],c));
}
void deltree(int x){
if(!x)return;
deltree(T[x].l);deltree(T[x].r);
getn[++rub]=x;
}
//Trie end
//Scapegoat begin
inline void up(int x){
mv[x]=info(ex[x]?val[x]:0,0);
if(son[x][0])mv[x]=merge(mv[x],mv[son[x][0]]);
if(son[x][1])mv[x]=merge(mv[x],mv[son[x][1]]);
}
inline int newnode(int p,int fa){
int x=++tot;
f[x]=fa;size[x]=real[x]=ex[x]=1;son[x][0]=son[x][1]=0;
val[x]=p;
mv[x]=info(p,0);
Ins(h[x]=0,inf,p,1);
return x;
}
inline int Newnode(int x,int fa){
f[x]=fa;size[x]=1;real[x]=ex[x];son[x][0]=son[x][1]=0;
mv[x]=info(ex[x]?val[x]:0,0);
h[x]=0;
return x;
}
int ins(int x,int p,int b){
size[x]++;real[x]++;mv[x]=merge(mv[x],info(p,0));
Ins(h[x],inf,p,1);
if(!son[x][b])return son[x][b]=newnode(p,x);else return ins(son[x][b],p,b);
}
void dfs(int x){
if(son[x][0])dfs(son[x][0]);
id[++cnt]=x;
if(son[x][1])dfs(son[x][1]);
}
int build(int fa,int l,int r){
int mid=(l+r)>>1,x=Newnode(id[mid],fa);
if(l<mid)size[x]+=size[son[x][0]=build(x,l,mid-1)],real[x]+=real[son[x][0]];
if(r>mid)size[x]+=size[son[x][1]=build(x,mid+1,r)],real[x]+=real[son[x][1]];
h[x]=Merge(h[son[x][0]],h[son[x][1]]);
if(ex[x])Ins(h[x],inf,val[x],1);
up(x);
return x;
}
inline int rebuild(int x){
cnt=0;dfs(x);
for(int i=1;i<=cnt;i++)deltree(h[id[i]]);
return build(f[x],1,cnt);
}
inline int kth(int k,int p){
int x=root,rank;
while(1){
size[x]++;real[x]++;mv[x]=merge(mv[x],info(p,0));Ins(h[x],inf,p,1);
rank=real[son[x][0]]+1;
if(k==rank&&ex[x])return x;
if(k<rank)x=son[x][0];else k-=rank+ex[x]-1,x=son[x][1];
}
}
inline void kthchange(int k,int p){
int x=root,rank,del;
while(1){
rank=real[son[x][0]]+1;
if(k==rank&&ex[x])break;
if(k<rank)x=son[x][0];else k-=rank+ex[x]-1,x=son[x][1];
}
for(del=val[x],val[x]=p;x;x=f[x])Ins(h[x],inf,del,-1),Ins(h[x],inf,p,1),up(x);
}
inline void kthdel(int k){
int x=root,rank,del;
while(1){
rank=real[son[x][0]]+1;
if(k==rank&&ex[x])break;
if(k<rank)x=son[x][0];else k-=rank+ex[x]-1,x=son[x][1];
}
for(del=val[x],ex[x]=0;x;x=f[x])real[x]--,Ins(h[x],inf,del,-1),up(x);
}
inline void kthins(int k,int p){
if(!root){root=newnode(p,0);return;}
int x;
if(k==1)x=ins(root,p,0);
else if(k>n)x=ins(root,p,1);
else{
x=kth(k,p);
if(son[x][0])x=ins(son[x][0],p,1);else{
son[x][0]=newnode(p,x);
x=son[x][0];
}
}
int z=x,deep=0;while(f[z])z=f[z],deep++;
if(deep<log(tot)/log(1/A))return;
while((double)size[son[x][0]]<A*size[x]&&(double)size[son[x][1]]<A*size[x])x=f[x];
if(!x)return;
if(x==root){root=rebuild(x);return;}
int y=f[x],b=son[y][1]==x,now=rebuild(x);
son[y][b]=now;
}
inline void ask(int x,int a,int b,int c,int d){
if(!x)return;
if(c<=a&&b<=d){maxv=merge(maxv,mv[x]);if(h[x])pool[++cntpool]=h[x];return;}
int mid=a+real[son[x][0]];
if(ex[x]&&c<=mid&&mid<=d)maxv=merge(maxv,info(val[x],0)),one[++cntone]=val[x];
if(c<mid)ask(son[x][0],a,mid-1,c,d);
if(d>=mid+ex[x])ask(son[x][1],mid+ex[x],b,c,d);
}
//Scapegoat end
inline void read(int&a){
char ch;while(!(((ch=getchar())>='0')&&(ch<='9')));
a=ch-'0';while(((ch=getchar())>='0')&&(ch<='9'))(a*=10)+=ch-'0';
}
int main(){
for(Pow[0]=i=1;i<=inf;i++)Pow[i]=Pow[i-1]<<1;
for(i=0;i<=inf;i++)Inv[i]=Pow[i]^1048575;
for(i=1;i<M;i++)getn[++rub]=i;
read(n);read(q);
for(i=1;i<=n;i++)read(val[i]),id[i]=i,ex[i]=1;
root=build(0,1,tot=n);
while(q--){
while(!(((ch=getchar())=='D')||(ch=='F')||(ch=='C')||(ch=='I')));
read(x);
if(ch!='D')read(y);
if(ch=='F'){
x=(x+ans)%n,y=(y+ans)%n;
maxv=info();cntpool=cntone=0;
ask(root,1,n,x+1,y+1);
ans=0;
Ask(maxv.v2);
printf("%d
",ans);
}else if(ch=='C')x=(x+ans)%n,y=(y+ans)&1048575,kthchange(x+1,y);
else if(ch=='I')x=(x+ans)%n,y=(y+ans)&1048575,kthins(x+1,y),n++;
else x=(x+ans)%n,kthdel(x+1),n--;
}
return 0;
}