luogu P4036 [JSOI2008]火星人

傳送門

好久之前xzz大佬就喊我作這題,結果如今才作qwq

由於要在序列中插入,因此直接用\(Splay\)維護這個串的哈希值,插入就直接把那個點插♂進去,修改就把點旋到根,而後修改和pushup,詢問的話能夠考慮二分,check就看兩個對應區間哈希值是否相等

#include<bits/stdc++.h>
#define LL long long
#define il inline
#define re register
#define ull unsigned long long

using namespace std;
const int N=150000+10;
il int rd()
{
  int x=0,w=1;char ch=0;
  while(ch<'0'||ch>'9') {if(ch=='-') w=-1;ch=getchar();}
  while(ch>='0'&&ch<='9') {x=(x<<3)+(x<<1)+(ch^48);ch=getchar();}
  return x*w;
}
int n,q;
char cc[N];
int rt,tt,fa[N],ch[N][2],sz[N];
ull a[N],ha[N],bs=377,bb[N];
il void psup(int x)
{
  sz[x]=sz[ch[x][0]]+sz[ch[x][1]]+1;
  ha[x]=ha[ch[x][0]]*bb[sz[ch[x][1]]+1]+a[x]*bb[sz[ch[x][1]]]+ha[ch[x][1]];
}
il void rot(int x)
{
  int y=fa[x],z=fa[y],yy=ch[y][1]==x,w=ch[x][!yy];
  ch[z][ch[z][1]==y]=x;fa[x]=z;
  ch[y][yy]=w;fa[w]=y;
  ch[x][!yy]=y,fa[y]=x;
  psup(y),psup(x);
}
il void spl(int x,int en)
{
  if(!x) return;
  while(fa[x]!=en)
    {
      int y=fa[x],z=fa[y];
      if(z!=en) ((ch[y][1]==x)^(ch[z][1]==y))?rot(x):rot(y);
      rot(x);
    }
  if(!en) rt=x;
}
il int gkth(int x)
{
  if(x<=0||x>n+2) return 0;
  int nw=rt;
  while(233)
    {
      if(x<=sz[ch[nw][0]]) nw=ch[nw][0];
      else if(x>sz[ch[nw][0]]+1) x-=sz[ch[nw][0]]+1,nw=ch[nw][1];
      else return nw;
    }
}
il int bui(int l,int r)
{
  if(l>r) return 0;
  int mid=(l+r)>>1,nw=++tt;
  sz[nw]=1,a[nw]=(cc[mid-1]>='a')?(ull)(cc[mid-1]-'a'):0;
  fa[ch[nw][0]=bui(l,mid-1)]=nw;
  fa[ch[nw][1]=bui(mid+1,r)]=nw;
  psup(nw);
  return nw;
}

int main()
{
  bb[0]=1;
  for(int i=1;i<=150000;++i) bb[i]=bb[i-1]*bs;
  scanf("%s",cc+1);
  n=strlen(cc+1);
  rt=bui(1,n+2);
  q=rd();
  char ss[2];
  while(q--)
    {
      scanf("%s",ss);
      if(ss[0]=='Q')
        {
          int x=rd(),y=rd();
          if(x>y) swap(x,y);
          int ll=gkth(x),rr=gkth(y),l=1,r=n-y+1,an=0;
          while(l<=r)
            {
              int mid=(l+r)>>1;
              ull h1,h2;
              int zz=gkth(x+mid+1);//x+mid-1+2
              spl(ll,0),spl(zz,ll),h1=ha[ch[zz][0]];
              zz=gkth(y+mid+1);
              spl(rr,0),spl(zz,rr),h2=ha[ch[zz][0]];
              if(h1==h2) an=mid,l=mid+1;
              else r=mid-1;
            }
          printf("%d\n",an);
        }
      else if(ss[0]=='R')
        {
          int x=gkth(rd()+1);
          scanf("%s",ss);
          spl(x,0),a[x]=ss[0]-'a',psup(x);
        }
      else
        {
          int x=gkth(rd()+1),nw=++tt;
          ++n;
          scanf("%s",ss);
          spl(x,0);
          a[nw]=ss[0]-'a',fa[nw]=x;
          fa[ch[x][1]]=nw,ch[nw][1]=ch[x][1],ch[x][1]=nw;
          psup(nw),psup(x);
        }
    }
  return 0;
}