bzoj1014: [JSOI2008]火星人prefix

题目大意：给你一个串，支持修改，插入，询问两点的lcp

用一个splay搞搞，每个点上维护hash值，询问就先二分，在比较hash值，可以过的

#include<cstdio>#include<cstring>#include<iostream>#include<algorithm>typedef long long int64;using namespace std;const int maxn=100011,Index=131;char s[maxn]; int n;int64 power[maxn];void init(){    scanf("%s",s+1); n=strlen(s+1); s[0]=s[n+1]=0;}struct Tspy{    struct node{        node *c[2],*f; int sz,n,v; int64 h;        void clear(){c[0]=0; c[1]=0; f=0; h=-1; sz=1; n=2;}        void update(){            if (c[0]) h=c[0]->h; else h=0; h=h*Index+v;            if (c[1]) h=h*power[c[1]->sz]+c[1]->h;            sz=1; if (c[0]) sz+=c[0]->sz; if (c[1]) sz+=c[1]->sz;        }    }*root,e[maxn];    int tot;    int getv(char ch){return ch-'a'+7;}    void clear(){tot=0; root=build(s,0,n+1); root->f=0;}    node* newnode(){e[tot].clear(); return e+(tot++);}    node* build(char *s,int l,int r){        int mid=(l+r)>>1; node *x=newnode();        if (mid-1>=l) x->c[0]=build(s,l,mid-1),x->c[0]->f=x;        if (mid+1<=r) x->c[1]=build(s,mid+1,r),x->c[1]->f=x;        if (x->c[0]) x->c[0]->n=0; if (x->c[1]) x->c[1]->n=1;        x->v=getv(s[mid]); x->update(); return x;    }    void rotate(node *x){        node *y=x->f,*z=y->f; int nx=x->n,ny=y->n;        x->n=ny; x->f=z; if (ny!=2) z->c[ny]=x;        z=x->c[1-nx];        y->f=x; y->n=1-nx; x->c[1-nx]=y;        if (z) z->f=y,z->n=nx; y->c[nx]=z; y->update();    }    void splay(node *x){        while (x->n!=2){            if (x->n==x->f->n) rotate(x->f); else rotate(x);            if (x->n!=2) rotate(x);        }        x->update(); root=x;    }    void modify(node *x,int v){        splay(x); x->v=v; x->update();    }    node* find(node *x,int rank){        for (;;){            int sz=0; if (x->c[0]) sz=x->c[0]->sz;            if (sz>=rank) {x=x->c[0]; continue;}            if (sz==rank-1) return x;            x=x->c[1]; rank-=sz+1;        }    }    void modify(int x,char ch){modify(find(root,x),getv(ch));}    void ins(int x,char ch){        node *a=find(root,x); ++n;        node *b=find(root,x+1);        splay(a); a->c[1]->n=2; a->c[1]->f=0; a->c[1]=0;        splay(b); node *c=newnode(); c->v=getv(ch);        b->f=c; b->n=1; c->c[1]=b; c->update();        c->f=a; c->n=1; a->c[1]=c; a->update();        root=a;    }    int64 geth(node *&x,node *&y){        splay(x); x->c[1]->f=0; x->c[1]->n=2; x->c[1]=0;        splay(y); int64 res=y->c[0]->h;        x->c[1]=y; y->f=x; y->n=1; x->update(); root=x;        return res;    }    bool check(node *&x,node *&y,node *&x1,node *&y1){        return geth(x,x1)==geth(y,y1);    }    int binary(int a,int b){        if (a>b) swap(a,b);        node *x=find(root,a-1),*y=find(root,b-1);        int t=1,w=n-b+2;        while (t<=w){            int mid=(t+w)>>1;            node *x1=find(root,a+mid),*y1=find(root,b+mid);            if (check(x,y,x1,y1)) t=mid+1; else w=mid-1;        }        return t-1;    }    void watch(node *x){        printf("Id=%d f=%d n=%d lc=%d rc=%d v=%d sz=%d\n",            x-e,x->f-e,x->n,x->c[0]-e,x->c[1]-e,x->v,x->sz);        if (x->c[0]) watch(x->c[0]); if (x->c[1]) watch(x->c[1]);    }    void watch(){watch(root);}}t;void prepare(){    power[0]=1; for (int i=1;i<maxn;++i) power[i]=power[i-1]*Index;}void work(){    prepare(); t.clear();    int m; scanf("%d",&m); char op[5];    for (int i=1;i<=m;++i){        scanf("%s",op);        if (op[0]=='Q'){            int a,b;            scanf("%d%d",&a,&b); ++a,++b;            printf("%d\n",t.binary(a,b));        }        if (op[0]=='I'){            int x; char ch[3];            scanf("%d%s",&x,ch); ++x; t.ins(x,ch[0]);        }        if (op[0]=='R'){            int x; char ch[3];            scanf("%d%s",&x,ch); ++x; t.modify(x,ch[0]);        }    }}int main(){    init();    work();    return 0;}