UVAlive 7041 The Problem to Slow Down You（回文树）

#include <iostream>
#include <stdlib.h>
#include <algorithm>
#include <stdio.h>
#include <math.h>
#include <string.h>

using namespace std;
typedef long long int LL;
const int maxn=2e5+5;
char str1[maxn];
char str2[maxn];
int n;
LL ans;
struct Tree
{
const static int maxn=4e5+5;
int next[maxn][26];
int fail[maxn];
LL  cnt[maxn];
LL  cnt2[maxn];
int len[maxn];
int s[maxn];
int last,p,n;
int new_node(int x)
{
memset(next[p],0,sizeof(next[p]));
cnt[p]=0;
cnt2[p]=0;
len[p]=x;
return p++;
}
void init()
{
//memset(cnt,0,sizeof(cnt));
//memset(cnt2,0,sizeof(cnt2));
p=0;
new_node(0);
new_node(-1);
last=0;
n=0;
s[0]=-1;
fail[0]=1;
}
void init2()
{
last=0;
s[0]=-1;
fail[0]=1;
n=0;
}
int get_fail(int x)
{
while(s[n-len[x]-1]!=s
)
x=fail[x];
return x;
}
void 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;
}
cnt[last]++;
}
void add2(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;
}
cnt2[last]++;
}

void count()
{
for(int i=p-1;i>=0;i--)
cnt[fail[i]]+=cnt[i];
}
void count2()
{
for(int i=p-1;i>=0;i--)
cnt2[fail[i]]+=cnt2[i];
}
void fun()
{
for(int i=2;i<=p-1;i++)
{
ans+=cnt[i]*cnt2[i];
}
}

}tree;
int main()
{
scanf("%d",&n);
for(int j=1;j<=n;j++)
{
scanf("%s%s",str1,str2);
tree.init();
int len=strlen(str1);
int len1=strlen(str2);
for(int i=0;i<len;i++)
{
tree.add(str1[i]);
}
tree.count();
tree.init2();
ans=0;
for(int i=0;i<len1;i++)
{
tree.add2(str2[i]);
}
tree.count2();
tree.fun();
printf("Case #%d: %lld\n",j,ans);
}
return 0;
}