CF1793D

补完发现自己就是个弱智东西。

#include <bits/stdc++.h>
/*
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>
*/
using namespace std;

const double eps = 1e-10;
const double pi = 3.1415926535897932384626433832795;
const double eln = 2.718281828459045235360287471352;

#define f(i, a, b) for (int i = a; i <= b; i++)
#define scan(x) scanf("%d", &x)
#define mp make_pair
#define pb push_back
#define lowbit(x) (x&(-x))

#define fi first
#define se second
#define SZ(x) int((x).size())
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define summ(a) (accumulate(all(a), 0ll))

typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;

using ll=long long;

ll n,p[(int)2e5+9],q[(int)2e5+9],ans=1,l,r;
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin>>n;
    for(int i=1,x;i<=n;++i)cin>>x,p[x]=i;
    for(int i=1,x;i<=n;++i)cin>>x,q[x]=i;
    
    l=min(p[1],q[1]),r=max(p[1],q[1]);
    if(l>1)ans+=(l-1)*(l)/2ll;
    if(r<n)ans+=(n-r)*(n-r+1)/2ll;
    if(l!=r)ans+=(r-l-1)*(r-l)/2ll;
    for(int i=1;i<n;++i){
        l=min({l,q[i],p[i]}),r=max({r,q[i],p[i]});
        if((p[i+1]<=r&&p[i+1]>=l)||(q[i+1]<=r&&q[i+1]>=l))continue;
        ll L=0,R=n+1ll;
        if(p[i+1]<=l)L=max(L,p[i+1]);
        if(p[i+1]>=r)R=min(R,p[i+1]);
        if(q[i+1]>=r)R=min(R,q[i+1]);
        if(q[i+1]<=l)L=max(L,q[i+1]);
        ans+=(l-L)*(R-r);
    }
    cout<<ans;
    return 0;
}