[BZOJ3790] 神奇项链

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define maxn 50009
using namespace std;
 
char s[maxn*2],str[maxn*2];
int len,Len[maxn*2];
struct X{
    int l,r;
}xd[maxn*2];
 
bool cmp(X a,X b){
    if(a.l!=b.l)return a.l<b.l;
    else return a.r>b.r;
}
 
void getstr(){
    int k=0;str[k++]=‘$‘;
    for(int i=0;i<len;i++){
        str[k++]=‘#‘;str[k++]=s[i];
    }
    str[k++]=‘#‘;len=k;
}
 
void Manacher(){
    int mx=0,id;
    getstr();memset(Len,0,sizeof(Len));
    for(int i=1;i<len;i++){
        if(mx>i)Len[i]=min(Len[2*id-i],mx-i);
        else Len[i]=1;
        while(str[i+Len[i]]==str[i-Len[i]])Len[i]++;
        if(i+Len[i]>mx)mx=i+Len[i],id=i;
    }
}
 
int main(){
    while(scanf("%s",&s)!=EOF){
        len=strlen(s);
        Manacher();
        for(int i=1;i<len;i++){
            xd[i].l=i-Len[i]+1;xd[i].r=i+Len[i]-1;
        }
        sort(xd+1,xd+len,cmp);
        int ans=1,now=2,r=xd[1].r;
        while(r!=len-1){
            int mx=r;
            while(xd[now].l<=r&&now<len){
                mx=max(mx,xd[now].r);now++;
            }
            r=mx;ans++;
        }
        cout<<ans-1<<endl;
    }
    return 0;
}