#include <bits/stdc++.h>
#include "shoes.h"
#define ll long long
#define pb push_back
#define x first
#define y second
using namespace std;
int n;
vector<int> a,bit;
vector<vector<int>> pos;
void update(int x, int val)
{
for(;x<=n;x+=x&-x)
bit[x]+=val;
}
ll pre(int x)
{
ll ret=0;
for(;x>0;x-=x&-x)
ret+=bit[x];
return ret;
}
ll sm(int l, int r)
{
return pre(r)-pre(l-1);
}
ll count_swaps(vector<int> S)
{
ll ans=0;
n=S.size();
bit.resize(n+1);
a.pb(0);
for(int i=1;i<=n;i++) a.pb(1), update(i,1);
pos.resize(n/2+1);
for(int i=0;i<n;i++) pos[S[i]].pb(i+1);
vector<int> pt(n/2+1,0);
for(int i=1;i<=n;i++)
{
if(a[i]==0) continue;
ans+=sm(i+1,pos[S[i-1]][pt[S[i-1]]+1]-1);
a[i]=0, a[pos[S[i-1]][pt[S[i-1]]+1]]=0;
update(i,-1), update(pos[S[i-1]][pt[S[i-1]]+1],-1);
pt[S[i-1]]+=2;
}
return ans;
}
