玄关求跳qaq

#include <bits/stdc++.h>
using namespace std;
const int N=2e5+1;
int n,x,tot,t[N<<5],ls[N<<5],rs[N<<5];
long long s1,s2,ans;
void push_up(int p)
{
	t[p]=t[ls[p]]+t[rs[p]];
}
int bulid(int pl,int pr,int x)
{
	int p=++tot,m=(pl+pr)>>1;t[p]=1;
	if(pl==pr)	return p;
	if(x<=m)	ls[p]=bulid(pl,m,x);
	else	rs[p]=bulid(m+1,pr,x);
	return p;
}
int merge(int lp,int rp,int pl,int pr)
{
	if(!lp)	return rp;
	if(!rp)	return lp;
	if(pl==pr)
	{
		t[lp]+=t[rp];
		return lp;
	}
	int m=(pl+pr)>>1;
	s1+=(long long)t[ls[lp]]*t[rs[rp]];
	s2+=(long long)t[ls[rp]]*t[rs[lp]];
	ls[lp]=merge(ls[lp],ls[rp],pl,m);
	rs[lp]=merge(rs[lp],rs[rp],m+1,pr);
	push_up(lp);
	return lp;
}
int solve()
{
	cin>>x;
	if(x)	return bulid(1,n,x);
	s1=s2=0;
	int ls=solve(),rs=solve(),p=merge(ls,rs,1,n);
	ans+=min(s1,s2);
	return p;
}
int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin>>n;
	solve();
	cout<<ans;
	return 0;
}