bzoj1014 火星人 (hash+splay+二分答案)

求公共前缀的问题可以用hash+二分来解决，但这个是动态的，所以我们用平衡树来维护区间的hash值

复杂度$O(mlog^2n)$

 #include<bits/stdc++.h>
 #define CLR(a,x) memset(a,x,sizeof(a))
 using namespace std;
 typedef long long ll;
 typedef unsigned long long ull;
 typedef pair<int,int> pa;
 const int maxn=1e5+,P=;
 const ull RUA=1145141919810ll;

 inline ll rd(){
     ll x=;char c=getchar();int neg=;
     while(c<''||c>''){if(c=='-') neg=-;c=getchar();}
     while(c>=''&&c<='') x=x*+c-'',c=getchar();
     return x*neg;
 }

 int ch[maxn][],pct,fa[maxn],siz[maxn];
 char v[maxn],s[maxn];
 ull sum[maxn],bin[maxn];
 int M,rt;

 inline void print(int x){
     if(!x) return;
     print(ch[x][]);
     // printf("!%d %d %d %d\n",x,ch[x][0],ch[x][1],fa[x]);
     print(ch[x][]);
 }

 inline bool isrc(int x){return x==ch[fa[x]][];}

 inline void update(int x){
     siz[x]=siz[ch[x][]]+siz[ch[x][]]+;
     sum[x]=(sum[ch[x][]]*bin[]+v[x])*bin[siz[ch[x][]]]+sum[ch[x][]];
 }

 inline void rotate(int x){
     int f=fa[x],ff=fa[f];bool b=isrc(x);
     if(ff) ch[ff][isrc(f)]=x; fa[x]=ff;
     if(ch[x][!b]) fa[ch[x][!b]]=f; ch[f][b]=ch[x][!b];
     fa[f]=x;ch[x][!b]=f;
     update(f),update(x);
 }

 inline void splay(int x,int tar){
     while(fa[x]!=tar&&fa[fa[x]]!=tar){
         if(isrc(x)==isrc(fa[x])) rotate(fa[x]);
         else rotate(x);rotate(x);
     }if(fa[x]!=tar) rotate(x);
     if(!tar) rt=x;
 }

 inline int findkth(int k){
     if(k>pct) return ;
     int x=rt;
     while(){
         int w=siz[ch[x][]];
         if(k<=w) x=ch[x][];
         else if(k==w+) return x;
         else k-=w+,x=ch[x][];
     }
 }

 inline void insert(int x,char y){
     int p=findkth(x+);
     splay(p,);
     int q=findkth(x+);
     splay(q,p);
     int n=++pct;
     sum[n]=v[n]=y,siz[n]=;fa[n]=q,ch[q][]=n;
     splay(n,);
 }

 inline void change(int x,char y){
     int p=findkth(x+);
     v[p]=y;update(p);
     splay(p,);
 }

 inline ull query(int x,int y){
     int p=findkth(x);
     if(!p) return RUA;
     splay(p,);
     int q=findkth(y+);
     if(!q) return RUA;
     splay(q,p);
     return sum[ch[q][]];
 }

 int main(){
     //freopen("","r",stdin);
     int i,j,k;
     bin[]=;for(i=;i<=1e5;i++) bin[i]=bin[i-]*P;
     ch[rt=][]=;siz[]=;
     fa[pct=]=;siz[]=;
     scanf("%s",s+);int len=strlen(s+);
     for(i=;i<=len;i++){
         insert(i-,s[i]);
     }
     M=rd();
     for(i=;i<=M;i++){
         char op[];scanf("%s",op);
         if(op[]=='Q'){
             int x=rd(),y=rd();
             int l=,r=pct-,ans=;
             while(l<=r){
                 int m=l+r>>;
                 ull a=query(x,x+m-),b=query(y,y+m-);
                 if(a==b&&a!=RUA) ans=m,l=m+;
                 else r=m-;
             }
             printf("%d\n",ans);
         }else if(op[]=='I'){
             int x=rd();scanf("%s",op);
             insert(x,op[]);
         }else{
             int x=rd();scanf("%s",op);
             change(x,op[]);
         }
     }
     return ;
 }