后缀平衡树+线段树。

$O(1)$比较大小的标号法真是强大。

#include<cstdio>
#include<cmath>
#define N 300010
#define M 500010
using namespace std;
typedef unsigned long long ll;
const ll inf=1ULL<<63;
const double A=0.8;
ll tl[N],tr[N],tm[N];
int size[N],son[N][2],f[N],v[N],tot,root,id[N],cnt;
char s[N],ch;
inline void read(int&a){char c;while(!(((c=getchar())>='0')&&(c<='9')));a=c-'0';while(((c=getchar())>='0')&&(c<='9'))(a*=10)+=c-'0';}
inline bool cmp(int a,int b){return s[a]==s[b]?tm[a-1]>tm[b-1]:s[a]>s[b];}
int ins(int x,int p){
int b=cmp(p,v[x]);
if(!son[x][b]){
son[x][b]=++tot;f[tot]=x;v[tot]=p;
if(!b)tl[tot]=tl[x],tr[tot]=tm[x];else tl[tot]=tm[x],tr[tot]=tr[x];
tm[tot]=(tl[tot]+tr[tot])>>1;
return tot;
}else return ins(son[x][b],p);
}
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,ll a,ll b){
int mid=(l+r)>>1,x=id[mid];
f[x]=fa;son[x][0]=son[x][1]=0;size[x]=1;tl[x]=a;tr[x]=b;tm[x]=(a+b)>>1;
if(l==r)return x;
if(l<mid)size[x]+=size[son[x][0]=build(x,l,mid-1,a,tm[x])];
if(r>mid)size[x]+=size[son[x][1]=build(x,mid+1,r,tm[x],b)];
return x;
}
inline int rebuild(int x){
cnt=0;dfs(x);return build(f[x],1,cnt,tl[x],tr[x]);
}
inline void insert(int p){
if(!root){root=tot=size[1]=1;v[1]=p;tr[1]=inf,tm[1]=inf>>1;return;}
int x=ins(root,p);
int deep=0,z=x;while(z)size[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;
}
int l[M<<1],r[M<<1],min[M<<1],seq[M],TOT;
void build(int a,int b){
int x=++TOT;
if(a==b){min[x]=a;return;}
int mid=(a+b)>>1;
l[x]=TOT+1;build(a,mid);
r[x]=TOT+1;build(mid+1,b);
min[x]=tm[seq[min[l[x]]]]<=tm[seq[min[r[x]]]]?min[l[x]]:min[r[x]];
}
void change(int x,int a,int b,int c){
if(a==b)return;
int mid=(a+b)>>1;
if(c<=mid)change(l[x],a,mid,c);else change(r[x],mid+1,b,c);
min[x]=tm[seq[min[l[x]]]]<=tm[seq[min[r[x]]]]?min[l[x]]:min[r[x]];
}
int ask(int x,int a,int b,int c,int d){
if(c<=a&&b<=d)return min[x];
int mid=(a+b)>>1,i,j;
if(d<=mid)return ask(l[x],a,mid,c,d);
if(c>mid)return ask(r[x],mid+1,b,c,d);
i=ask(l[x],a,mid,c,d),j=ask(r[x],mid+1,b,c,d);
return tm[seq[i]]<=tm[seq[j]]?i:j;
}
int n,m,i,x,y,len,type,ans;
int main(){
read(n);read(m);read(len);read(type);
for(getchar(),i=1;i<=len;i++)s[len-i+1]=getchar();
for(i=1;i<=len;i++)insert(i);
for(i=1;i<=n;i++)read(seq[i]);
build(1,n);
while(m--){
while(!(((ch=getchar())=='I')||(ch=='C')||(ch=='Q')));read(x);
if(ch=='I')s[++len]=(x^ans*type)+'a',insert(len);
if(ch=='C')read(seq[x]),change(1,1,n,x);
if(ch=='Q')read(y),printf("%d\n",ans=ask(1,1,n,x,y));
}
return 0;
}