bzoj 1014 splay

　　首先我们可以用splay来维护这个字符串，那么对于某两个位置的lcp，维护每个节点的子树的hash，然后二分判断就好了。

/**************************************************************

    Problem: 1014

    User: BLADEVIL

    Language: C++

    Result: Accepted

    Time:4468 ms

    Memory:3640 kb

****************************************************************/

 

//By BLADEVIL

#include <cstdio>

#include <cstring>

#include <algorithm>

#define maxn 100010

 

using namespace std;

 

char s[maxn];

int fac[maxn],key[maxn],num,rot,son[maxn][2],father[maxn],size[maxn],hash[maxn];

 

void update(int x) {

    if (!x) return ;

    hash[x]=hash[son[x][0]]+(key[x]+hash[son[x][1]]*27)*fac[size[son[x][0]]];

    size[x]=size[son[x][0]]+size[son[x][1]]+1;

}

 

int build(int l,int r) {

    int mid=l+r>>1,left=0,right=0;

    if (mid<r) right=build(mid+1,r);

    if (mid>l) left=build(l,mid-1);

    father[left]=father[right]=mid;

    son[mid][0]=left; son[mid][1]=right;

    update(mid);

    return mid;

}

 

void rotate(int x,int &rot) {

    int y=father[x],z=father[y];

    int p=(son[y][1]==x),q=p^1;

    if (y==rot) rot=x; else if (son[z][0]==y) son[z][0]=x; else son[z][1]=x;

    father[x]=z; father[y]=x; father[son[x][q]]=y;

    son[y][p]=son[x][q]; son[x][q]=y;

    update(y);

}

 

void splay(int x,int &rot) {

    while (x!=rot) {

        int y=father[x],z=father[y];

        if (y!=rot)

            if ((son[y][0]==x)^(son[z][0]==y)) rotate(x,rot); else rotate(y,rot);

        rotate(x,rot);

    }

    update(x);

}

 

int find(int x) {

    int t=rot;

    while (1) {

        if (size[son[t][0]]+1==x) return t; else

        if (size[son[t][0]]+1>x) t=son[t][0]; else

        if (size[son[t][0]]+1<x) x-=size[son[t][0]]+1,t=son[t][1];

    }

}

 

bool judge(int x,int y,int len) {

    if (len==1) return key[find(x+1)]==key[find(y+1)];

    int p=find(x),q=find(x+len+1);

    splay(p,rot); splay(q,son[rot][1]);

    int a1=hash[son[q][0]];

    p=find(y); q=find(y+len+1);

    splay(p,rot); splay(q,son[rot][1]);

    int a2=hash[son[q][0]];

    return a1==a2;

}

 

int main() {

    scanf("%s",&s); num=strlen(s);

    fac[0]=1; for (int i=1;i<maxn;i++) fac[i]=fac[i-1]*27;

    for (int i=2;i<=num+1;i++) key[i]=s[i-2]-'a'+1; num+=2;

    rot=build(1,num);

    int task; scanf("%d",&task);

    while (task--) {

        int x,y;

        scanf("%s",&s);

        if (s[0]=='Q') {

            scanf("%d%d",&x,&y);

            if (x>y) swap(x,y);

            int l=1,r=num-y-1,mid,ans=0;

            while (l<=r) {

                mid=l+r>>1;

                if (judge(x,y,mid)) ans=mid, l=mid+1; else r=mid-1;

            }

            printf("%d\n",ans);

        } else

        if (s[0]=='R') {

            scanf("%d%s",&x,&s);

            int p=find(x+1);

            key[p]=s[0]-'a'+1;

            splay(p,rot);

        } else

        if (s[0]=='I') {

            scanf("%d%s",&x,&s);

            key[++num]=s[0]-'a'+1;

            int p=find(x+1); splay(p,rot);

            int q=find(x+2); splay(q,son[rot][1]);

            father[num]=q; son[q][0]=num;

            splay(num,rot);

        }

     

    }

    return 0;   

}