#include <bits/stdc++.h>
using namespace std;
vector<int> tree;
void upd(int v, int i, int l, int r) {
if (l == r) tree[v]++;
else {
int middle = (l + r) / 2;
if (i <= middle) upd(2 * v, i, l, middle);
else upd(2 * v + 1, i, middle + 1, r);
tree[v] = tree[2 * v] + tree[2 * v + 1];
}
}
int query(int v, int ql, int qr, int l, int r) {
if (ql <= l && r <= qr) return tree[v];
if (r < ql || qr < l) return 0;
int middle = (l + r) / 2;
int left = query(2 * v, ql, qr, l, middle);
int right = query(2 * v + 1, ql, qr, middle + 1, r);
return left + right;
}
long long count_swaps(vector<int> nums) {
int n = nums.size() / 2;
vector<vector<int>> left(n + 1);
vector<vector<int>> right(n + 1);
for (int i = 0; i < 2 * n; i++) {
if (nums[i] < 0) left[-nums[i]].push_back(i);
else right[nums[i]].push_back(i);
}
vector<pair<int, int>> segs;
long long ans = 0;
for (int i = 0; i <= n; i++) {
int s = left[i].size();
for (int j = 0; j < s; j++) {
int l = left[i][j];
int r = right[i][j];
if (l > r) {
ans++;
swap(l, r);
}
segs.push_back({l, r});
}
}
sort(segs.begin(), segs.end());
vector<int> arr(2 * n);
for (int i = 0; i < n; i++) {
arr[segs[i].first] = i;
arr[segs[i].second] = i;
}
tree.resize(4 * n, 0);
for (int i = 0; i < 2 * n; i++) {
int val = arr[i];
int add = val == n - 1? 0: query(1, val + 1, n - 1, 0, n - 1);
ans += (long long) add;
upd(1, val, 0, n - 1);
}
return ans;
}
