【bzoj1014】: [JSOI2008]火星人prefix 平衡树-字符串-hash-二分

【bzoj1014】: [JSOI2008]火星人

用平衡树维护字符串的hash

然后询问的时候二分一下就好了

 /* http://www.cnblogs.com/karl07/ */
 #include <cstdlib>
 #include <cstdio>
 #include <cstring>
 #include <cmath>
 #include <algorithm>
 using namespace std;
 #define ull unsigned long long

 const int N=;
 const int P=;
 struct tre{
     int key,sz,t;
     ull hash;
     tre *ls,*rs;
 }t[N*],*NEW=t,*null=t,*root,*r1,*r2,*r3;
 ull base[N];
 char s[N];
 int n;

 inline tre *new1(int x){
     NEW++;
     NEW->t=x;
     NEW->key=rand();
     NEW->sz=;
     NEW->hash=x;
     NEW->ls=NEW->rs=null;
     return NEW;
 }

 inline void update(tre *p){
     p->sz=p->ls->sz++p->rs->sz;
     p->hash=p->ls->hash*base[p->rs->sz+]+p->t*base[p->rs->sz]+p->rs->hash;
 }

 void merge(tre *&p,tre *x,tre *y){
     if (x==null) { p=y; return; }
     if (y==null) { p=x; return; }
     if (x->key>y->key){
         p=x;
         merge(p->rs,p->rs,y);
     }else{
         p=y;
         merge(p->ls,x,p->ls);
     }
     update(p);
 }

 void split(tre *p,tre *&x,tre *&y,int k){
     if (k==) { x=null,y=p; return; }
     if (k==p->sz) { y=null,x=p; return; }
     if (k>=p->ls->sz+){
         x=p;
         split(p->rs,p->rs,y,k-p->ls->sz-);
     }else{
         y=p;
         split(p->ls,x,p->ls,k);
     }
     update(p);
 }

 void HASH(){
     null->ls=null->rs=null;
     null->hash=;
     null->sz=null->t=;
     null->key=-;
     root=null;
     base[]=;
     for (int i=;i<N;i++) base[i]=base[i-]*P;
 }

 inline ull Q(tre *p,int l,int x){
     ull ans;
     split(root,r1,r2,l-);
     split(r2,r2,r3,x);
     ans=r2->hash;
     merge(r2,r2,r3);
     merge(root,r1,r2);
     return ans;
 }

 inline void R(int l,int x){
     split(root,r1,r2,l-);
     split(r2,r2,r3,);
     merge(r1,r1,new1(x));
     merge(root,r1,r3);
 }

 inline void I(int l,int x){
     split(root,r1,r2,l);
     merge(r1,r1,new1(x));
     merge(root,r1,r2);
 }

 inline int query(int x,int y){
     if (x>y) swap(x,y);
     int l=,r=root->sz-y+,ans=;
     while (l<=r){
         int mid=(l+r)/;
         ull a1=Q(root,x,mid),a2=Q(root,y,mid);
         if (a1==a2){
             ans=mid;
             l=mid+;
         }else{
             r=mid-;
         }
     }
     return ans;
 }

 int main(){
     HASH();
     scanf("%s",s);
     scanf("%d",&n);
     for (int i=,l=strlen(s);i<=l-;i++){
         merge(root,root,new1(s[i]));
     }
     for (int i=,x,y;i<=n;i++){
         char ss[],s1[];
         scanf("%s",ss);
         if (ss[]=='Q') { scanf("%d%d",&x,&y); printf("%d\n",query(x,y)); }
         if (ss[]=='R') { scanf("%d%s",&x,s1); R(x,s1[]);}
         if (ss[]=='I') { scanf("%d%s",&x,s1); I(x,s1[]);}
     }
     return ;
 }

并不会splay。。只会非旋转treap。。10s正好卡过去。。药丸