【bzoj1014】 JSOI2008—火星人prefix

#include<algorithm>
#include<iostream>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<cmath>
#define LL long long
#define inf 2147483640
#define MOD 9875321
#define Pi acos(-1.0)
#define free(a) freopen(a".in","r",stdin),freopen(a".out","w",stdout);
using namespace std;

const int maxn=150010;
int tr[maxn][2],fa[maxn],id[maxn],size[maxn];
int v[maxn],h[maxn],bin[maxn];
int n,rt,sz,q;
char s[maxn];

void update(int k) {
	int l=tr[k][0],r=tr[k][1];
	size[k]=size[l]+size[r]+1;
	h[k]=h[l]+(LL)v[k]*bin[size[l]]%MOD+(LL)bin[size[l]+1]*h[r]%MOD;
	h[k]%=MOD;
}
void rotate(int x,int &k) {
	int y=fa[x],z=fa[y],l,r;
	l=tr[y][1]==x;r=l^1;
	if (y==k) k=x;
	else tr[z][tr[z][1]==y]=x;
	fa[x]=z;fa[y]=x;fa[tr[x][r]]=y;
	tr[y][l]=tr[x][r];tr[x][r]=y;
	update(y);update(x);
}
void splay(int x,int &k) {
	while (x!=k) {
		int y=fa[x],z=fa[y];
		if (y!=k) {
			if ((tr[z][0]==y) ^ (tr[y][0]==x)) rotate(x,k);
			else rotate(y,k);
		}
		rotate(x,k);
	}
}
int find(int k,int x) {
	int l=tr[k][0],r=tr[k][1];
	if (size[l]+1==x) return k;
	else if (size[l]>=x) return find(l,x);
	else return find(r,x-size[l]-1);
}
void insert(int k,int val) {
	int x=find(rt,k+1),y=find(rt,k+2);
	splay(x,rt);splay(y,tr[x][1]);
	int z=++sz;tr[y][0]=z;fa[z]=y;v[z]=val;
	update(z);update(y);update(x);
}
int query(int k,int val) {
	int x=find(rt,k),y=find(rt,k+val+1);
	splay(x,rt);splay(y,tr[x][1]);
	return h[tr[y][0]];
}
int solve(int x,int y) {
	int l=1,r=min(sz-x,sz-y)-1,ans=0;
	while (l<=r) {
		int mid=(l+r)>>1;
		if (query(x,mid)==query(y,mid)) l=mid+1,ans=mid;
		else r=mid-1;
	}
	return ans;
}
void build(int l,int r,int f) {
	if (l>r) return;
	int mid=(l+r)>>1,now=id[mid],last=id[f];
	if (l==r) {
		v[now]=h[now]=s[mid]-‘a‘+1;
		fa[now]=last;size[now]=1;
		tr[last][mid>=f]=now;
		return;
	}
	build(l,mid-1,mid);build(mid+1,r,mid);
	v[now]=s[mid]-‘a‘+1;fa[now]=last;update(now);
	tr[last][mid>=f]=now;
}
int main() {
	scanf("%s",s+2);
	n=strlen(s+2);
	bin[0]=1;for (int i=1;i<maxn;i++) bin[i]=bin[i-1]*31%MOD;
	for (int i=1;i<=n+2;i++) id[i]=i;
	build(1,n+2,0);rt=(n+3)>>1;sz=n+2;
	scanf("%d",&q);
	while (q--) {
		int x,y;char ch[10];
		scanf("%s",ch);
		scanf("%d",&x);
		if (ch[0]==‘Q‘) scanf("%d",&y),printf("%d\n",solve(x,y));
		if (ch[0]==‘R‘) {
			scanf("%s",ch);
			x=find(rt,x+1);splay(x,rt);
			v[rt]=ch[0]-‘a‘+1;update(rt);
		}
		if (ch[0]==‘I‘) scanf("%s",ch),insert(x,ch[0]-‘a‘+1);
	}
	return 0;
}