http://www.51nod.com/onlineJudge/questionCode.html#!problemId=1832
题意：
思路：
官方题解如下：
可以看一下这篇文章：https://wenku.baidu.com/view/a2a45aa0284ac850ad024261.html
#include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>
using namespace std;
const int maxn = +;
const int inf = 0x3f3f3f3f; int n;
int a[maxn],b[maxn]; struct BigInt
{
const static int mod = ;
const static int DLEN = ;
int a[],len;
BigInt()
{
memset(a,,sizeof(a));
len = ;
}
BigInt(int v)
{
memset(a,,sizeof(a));
len = ;
do
{
a[len++] = v%mod;
v /= mod;
}while(v);
}
BigInt(const char s[])
{
memset(a,,sizeof(a));
int L = strlen(s);
len = L/DLEN;
if(L%DLEN)len++;
int index = ;
for(int i = L-;i >= ;i -= DLEN)
{
int t = ;
int k = i - DLEN + ;
if(k < )k = ;
for(int j = k;j <= i;j++)
t = t* + s[j] - '';
a[index++] = t;
}
}
BigInt operator +(const BigInt &b)const
{
BigInt res;
res.len = max(len,b.len);
for(int i = ;i <= res.len;i++)
res.a[i] = ;
for(int i = ;i < res.len;i++)
{
res.a[i] += ((i < len)?a[i]:)+((i < b.len)?b.a[i]:);
res.a[i+] += res.a[i]/mod;
res.a[i] %= mod;
}
if(res.a[res.len] > )res.len++;
return res;
}
BigInt operator *(const BigInt &b)const
{
BigInt res;
for(int i = ; i < len;i++)
{
int up = ;
for(int j = ;j < b.len;j++)
{
int temp = a[i]*b.a[j] + res.a[i+j] + up;
res.a[i+j] = temp%mod;
up = temp/mod;
}
if(up != )
res.a[i + b.len] = up;
}
res.len = len + b.len;
while(res.a[res.len - ] == &&res.len > )res.len--;
return res;
}
void output()
{
printf("%d",a[len-]);
for(int i = len-;i >= ;i--)
printf("%04d",a[i]);
printf("\n");
}
};
BigInt ans; void dfs(int al, int ar, int bl, int br)
{
if(ar-al<=) return;
al++;
br--;
int cnt = ;
int index = bl;
while(a[al]!=b[index]) index++;
int newar = al+index-bl+;
int newbl = index+;
cnt++;
dfs(al,newar-,bl,index);
if(ar-al!=index-bl)
{
cnt++;
dfs(newar,ar,newbl,br);
}
if(cnt==) ans=ans*;
} int main()
{
//freopen("in.txt","r",stdin);
ans = ;
scanf("%d",&n);
for(int i=;i<n;i++) scanf("%d",&a[i]);
for(int i=;i<n;i++) scanf("%d",&b[i]);
dfs(,n-,,n-);
ans.output();
return ;
}