URAL 2040 Palindromes and Super Abilities 2(回文树)

#include <iostream>
#include <string.h>

#include <stdlib.h>
#include <math.h>
#include <stdio.h>

using namespace std;
typedef long long int LL;
const int MAX=5*1e6;
const int maxn=4*1e6+5;
char str[MAX+5];
struct Tree
{
    int next[maxn][2];
    int fail[MAX+5];
    int len[MAX+5];
    int s[MAX+5];
    int last,n,p;
    int new_node(int x)
    {
        memset(next[p],0,sizeof(next[p]));
        len[p]=x;
        return p++;
    }
    void init()
    {
        p=0;
        new_node(0);
        new_node(-1);
        last=0;n=0;
        s[0]=-1;
        fail[0]=1;
	}
    int get_fail(int x)
    {
        while(s[n-len[x]-1]!=s[n])
            x=fail[x];
        return x;
    }
    int add(int x)
    {
        x-='a';
        s[++n]=x;
        int cur=get_fail(last);
        if(!(last=next[cur][x]))
        {
            int now=new_node(len[cur]+2);
            fail[now]=next[get_fail(fail[cur])][x];
            next[cur][x]=now;
            last=now;
            return 1;
        }
        return 0;
    }

}tree;
char ans[MAX+5];
int main()
{
    while(scanf("%s",str)!=EOF)
    {
       
        tree.init();
		int i;
        for( i=0;str[i];i++)
        {
			if(!tree.add(str[i]))
			    ans[i]='0';
			else
				ans[i]='1';
		}
		ans[i]='\0';
		puts(ans);
	}
    return 0;
}