P4036 [JSOI2008]火星人（splay+hash+二分）

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
typedef unsigned long long ull;
int read(){
    char c=getchar(); int x=0;
    while(c<‘0‘||c>‘9‘) c=getchar();
    while(‘0‘<=c&&c<=‘9‘) x=x*10+c-48,c=getchar();
    return x;
}
#define N 300005
const int bas=13331;
int n,Q; char q[N],q1[3]; ull ha[N];
struct node{int ch[2],sz,fa; ull vl,w;}a[N];
struct Splay{
    #define lc a[x].ch[0]
    #define rc a[x].ch[1]
    #define mid (l+r)/2
    int rt,u;
    inline void up(int x){
        a[x].sz=a[lc].sz+a[rc].sz+1,
        a[x].vl=a[lc].vl*ha[a[rc].sz+1]+a[x].w*ha[a[rc].sz]+a[rc].vl; 
    }
    inline int whi(int y,int x){return a[y].ch[1]==x;}
    void turn(int x,int &k){
        int y=a[x].fa,z=a[y].fa,l=whi(y,x),r=l^1;
        if(y==k) k=x;
        else a[z].ch[whi(z,y)]=x;
        a[a[x].ch[r]].fa=y; a[y].fa=x; a[x].fa=z;
        a[y].ch[l]=a[x].ch[r]; a[x].ch[r]=y;
        up(y); up(x);
    }
    void splay(int x,int &k){
        for(;x!=k;turn(x,k)){
            int y=a[x].fa,z=a[y].fa;
            if(y!=k) turn(whi(z,y)==whi(y,x)?y:x,k);
        }
    }
    int kth(int k){
        int x=rt;
        while(a[lc].sz+1!=k){
            if(a[lc].sz>=k) x=lc;
            else k=k-a[lc].sz-1,x=rc;
        }return x;
    }
    inline void rep(int x,ull k){a[x=kth(x)].w=k,splay(x,rt);}
    void ins(int x,ull k){
        x=kth(x); ++u;
        if(!rc) rc=u;
        else{for(x=rc;lc;x=lc); lc=u;}
        a[u].fa=x; a[u].w=k; up(u); splay(u,rt);
    }
    ull Fi(int x,int y){
        int L=kth(x-1),R=kth(y+1);
        splay(L,rt); splay(R,a[L].ch[1]);
        return a[a[R].ch[0]].vl;
    }
    int ask(int x,int y){
        if(x>y) swap(x,y);
        int l=1,r=u-y,re=0;
        while(l<=r){
            if(Fi(x,x+mid-1)!=Fi(y,y+mid-1)) r=mid-1;
            else re=mid,l=mid+1;
        }return re;
    }
    int build(int Fa,int l,int r){
        a[mid].w=(ull)q[mid-1]; a[mid].fa=Fa; ++u;
        if(l<mid) a[mid].ch[0]=build(mid,l,mid-1);
        if(r>mid) a[mid].ch[1]=build(mid,mid+1,r);
        up(mid); return mid;
    }
}S;
int main(){
    scanf("%s",q+1); n=strlen(q+1); ha[0]=1;
    for(int i=1;i<N;++i) ha[i]=ha[i-1]*bas;
    S.rt=S.build(0,1,n+2); Q=read();//建树时记得加入边界
    for(int i=1,w1,w2;i<=Q;++i){
        scanf("%s",q1);
        if(q1[0]==‘Q‘) w1=read(),w2=read(),printf("%d\n",S.ask(w1+1,w2+1));
        if(q1[0]==‘R‘) w1=read(),scanf("%s",q1),S.rep(w1+1,(ull)q1[0]);
        if(q1[0]==‘I‘) w1=read(),scanf("%s",q1),S.ins(w1+1,(ull)q1[0]);
    }return 0;
}