#include <bits/stdc++.h>
using namespace std;
#define ll long long
struct BIT {
vector<int> fen;
int N;
BIT(int _N) {
N = _N + 5;
fen = vector<int>(N + 5, 0);
}
void upd(int x, int v) {
x++;
while(x <= N) {
fen[x] += v;
x += (x & -x);
}
}
int prefix(int x) {
x++;
int res = 0;
while(x > 0) {
res += fen[x];
x -= x & -x;
}
return res;
}
int query(int l, int r) {
return prefix(r) - prefix(l - 1);
}
};
deque<int> pos[2][100001];
ll count_swaps(vector<int> S) {
int N = S.size();
int n = N / 2;
for(int i = 0; i < N; ++i) {
if(S[i] < 0) {
pos[0][-S[i]].push_back(i);
}
else {
pos[1][S[i]].push_back(i);
}
}
BIT bit(N);
for(int i = 0; i < N; ++i) {
bit.upd(i, 1);
}
ll answer = 0;
vector<bool> used(N, 0);
int counter = 0, i = 0;
while(counter < n) {
if(used[i]) {
i++;
continue;
}
if(S[i] < 0) {
pos[0][-S[i]].pop_front();
int j = pos[1][-S[i]].front(); pos[1][-S[i]].pop_front();
answer += (ll)bit.query(i, j) - 2;
bit.upd(i, -1); used[i] = 1;
bit.upd(j, -1); used[j] = 1;
}
else {
pos[1][S[i]].pop_front();
int j = pos[0][S[i]].front(); pos[0][S[i]].pop_front();
answer += (ll)bit.query(i, j) - 1;
bit.upd(i, -1); used[i] = 1;
bit.upd(j, -1); used[j] = 1;
}
counter++;
i++;
}
return answer;
}
