nlog(n)求lcs

把S1中的字符按照s2中的位置进行存储，按s1的位置顺序倒着存进新的序列里，求个LIS即可。

include

include

include

include

using namespace std;
const int M = 110000;
vector A[M];
int s[M],t[M];
vector l;
int dp[M],len;
int main(){
int n;
scanf("%d",&n);
n=n*5;
for(int i=1;i<=n;++i)scanf("%d",&s[i]);
for(int i=1;i<=n;++i)scanf("%d",&t[i]);
for(int i=n;i>=1;--i)A[t[i]].push_back(i);
for(int i=1;i<=n;++i){
if(!A[s[i]].empty()){
for(auto it:A[s[i]]){
l.push_back(it);
}
}else l.push_back(0);
}
int len=0;
for(auto it:l){
if(it>dp[len]){
dp[++len] = it;
continue;
}
int pos = lower_bound(dp+1,dp+1+len,it)-dp;
if(dp[pos]>it)dp[pos] = it;
}
printf("%d\n",len);
return 0;
}