# include <bits/stdc++.h>
# pragma GCC optimize("Ofast")
# define file
# define ll long long
# define fi first
# define se second
# define pb push_back
# define pf push_front
# define For(i, a, b) for( ll i = a; i < b; i++ )
# define in insert
# define all(a) a.begin(),a.end()
# define pi pair < ll, ll >
# define readfile(file) freopen ( (file + ".in").c_str(), "r", stdin)
# define writefile(file) freopen ( (file + ".out").c_str(), "w", stdout)
# define speed ios_base::sync_with_stdio(false);cin.tie(NULL)
# define SET(file) readfile(file);writefile(file);
# define LARGE 100005
using namespace std;
ll count_swaps( vector < int > S ) {
ll cnt = 0;
int n = S.size();
ll c = 0;
ll x = 0;
For ( i, 0, n / 2 ) {
if ( S[i] < 0 && S[i] != S[i + n / 2] && abs(S[i]) == abs(S[i + n / 2]) ) {
c++;
}
if ( abs( S[i] ) == abs( S[i + n / 2] ) ) {
x++;
}
}
if ( c == n / 2 ) {
ll ans = n / 2 - 1;
ans *= n / 2;
ans /= 2;
return ans;
}
if ( x == n / 2 ) {
vector < int > ms, ps;
int sz1 = 0, sz2 = 0;
For ( i, 0, n ) {
if ( S[i] > 0 ) {
ps.pb(i);
sz1++;
}
else {
ms.pb(i);
sz2++;
}
}
For ( i, 0, n ) {
if ( sz2 && i >= ms[0] ) {
ms.erase(ms.begin());
sz2--;
}
if ( sz1 && i >= ps[0] ) {
ps.erase(ps.begin());
sz1--;
}
if ( S[i] != S[i + 1] && abs(S[i]) == abs(S[i]) && S[i] < 0 ) {
i++;
}
else {
if ( S[i] < 0 ) {
for ( int j = ps[0]; j > i + 1; j-- ) {
swap( S[j], S[j - 1] );
cnt++;
}
ps.erase(ps.begin());
sz1--;
}
else {
for ( int j = ms[0]; j > i; j-- ) {
swap(S[j], S[j - 1]);
cnt++;
}
ms.erase(ms.begin());
sz2--;
}
i++;
}
}
return cnt;
}
For ( i, 0, n - 1 ) {
if ( S[i] != S[i + 1] && abs(S[i]) == abs(S[i + 1]) && S[i] < 0 ) {
i++;
}
else {
For ( j, i + 1, n ) {
if ( S[i] != S[j] && abs(S[i]) == abs(S[j]) ) {
for ( int k = j; k > i + 1; k-- ) {
swap( S[k], S[k - 1] );
cnt++;
}
if ( S[i] > 0 ) {
swap( S[i], S[i + 1] );
cnt++;
}
break;
}
}
i++;
}
}
return cnt;
}
/*
int main() {
/// Author: _Dilshod_
#ifdef file
freopen("in.txt", "r", stdin);
freopen("out.txt", "w", stdout);
#endif // file
speed;
vector < int > S = {2, 1, -1, -2};
cout << count_swaps(S);
}
*/
