bzoj2555

开始时间：19:40

完成时间：21:00

传送门：http://www.lydsy.com/JudgeOnline/problem.php?id=2555

题目大意：(1):在当前字符串的后面插入一个字符串
    
   　　　  (2):询问字符串s在当前字符串中出现了几次？(作为连续子串)

题解：最近在写后缀自动机，求一个字符串中出现了几次就相当与其right集合大小，直接上parent树，因为后缀自动机构造特性，可能在parent树改变边，于是用lct维护；

代码：

 #include<algorithm>
 #include<iostream>
 #include<cstring>
 #include<cstdio>
 #include<cmath>
 #define maxn 1200005
 #define maxl 3000005
 using namespace std;
 int q,n,tot,root,last,mark,m,ri[maxn],lazy[maxn];
 char st[maxl];
 char ss[];
 struct data{
     int fa[maxn],son[maxn][];
     int isroot(int x) {return (son[fa[x]][]!=x && son[fa[x]][]!=x);}
     int which(int x){return son[fa[x]][]==x;}
     void change(int x,int k){ ri[x]+=k; lazy[x]+=k;}
     void pushdown(int x)
     {
         if (!lazy[x]) return;
         if (son[x][]) change(son[x][],lazy[x]);
         if (son[x][]) change(son[x][],lazy[x]);
         lazy[x]=;
     }
     void relax(int x){if (!isroot(x)) relax(fa[x]); pushdown(x);}
     void turn(int x){
         int y=fa[x],wx=which(x),wy=which(y);
         if (!isroot(y)) son[fa[y]][wy]=x; fa[x]=fa[y];
         son[y][wx]=son[x][-wx]; fa[son[x][-wx]]=y;
         son[x][-wx]=y; fa[y]=x;
     }
     void splay(int x)
     {
         relax(x);
         while (!isroot(x))
         {
             if (isroot(fa[x])) turn(x);
             else if (which(x)==which(fa[x])) turn(fa[x]),turn(x);
             else turn(x),turn(x);
         }
     }
     void access(int x)
     {
         for (int p=; x; x=fa[x]){ splay(x); son[x][]=p; p=x;}
     }
     void link(int x,int y){
         fa[x]=y; access(y); splay(y); change(y,ri[x]);
     }
     void cut(int x)
     {
         access(x); splay(x); change(son[x][],-ri[x]); fa[son[x][]]=; son[x][]=;
     }
 }lct;
 struct date{
     int fa[maxn],son[maxn][],val[maxn];
     void prepare(){root=tot=last=;}
     int newnode(int x){val[++tot]=x; return tot;}
     void extend(int x)
     {
         int p=last,np=newnode(val[p]+);ri[np]=;last=np;
         for (; p&&!son[p][x]; p=fa[p]) son[p][x]=np;
         if (!p) fa[np]=root,lct.link(np,root);
         else
         {
             int q=son[p][x];
             if (val[q]==val[p]+){fa[np]=q; lct.link(np,q);}
             else
             {
                 int nq=newnode(val[p]+);ri[nq]=;
                 memcpy(son[nq],son[q],sizeof(son[q]));
                 fa[nq]=fa[q]; lct.cut(q),lct.link(nq,fa[nq]);
                 fa[q]=fa[np]=nq; lct.link(q,nq),lct.link(np,nq);
                 for (; p && son[p][x]==q; p=fa[p]) son[p][x]=nq;
             }
         }
     }
     void build()
     {for (int i=; i<=m; i++) extend(st[i]-'A');}
     void query(){
         int x,y;
         bool can=;
         x=root;
         for (int i=;i<=m;i++){
             y=st[i]-'A';
             if (!son[x][y]){
                 can=;
                 break;
             }else{
                 x=son[x][y];
             }
         }
         if (can==||x==root) puts("");
         else{
             lct.splay(x);
             printf("%d\n",ri[x]),mark^=ri[x];
         }
     }
 }SAM;
 void unzip(){
     int temp=mark;
     for (int i=;i<=m;i++){
         temp=(temp*+i-)%m+;
         char t=st[i]; st[i]=st[temp],st[temp]=t,temp--;
     }
 }
 int main()
 {
     scanf("%d\n",&q);mark=;
     scanf("%s",st+); m=strlen(st+);
     SAM.prepare();
     SAM.build();
     for (int i=; i<=q; i++)
     {
         scanf("%s",ss);scanf("%s",st+); m=strlen(st+);unzip();
         if (ss[]=='A') SAM.build();
         else SAM.query();
     }
 }