#include "shoes.h"
// #include "grader.cpp"
#include <bits/stdc++.h>
using namespace std;
struct SegTree {
int size = 1;
vector<int> mins;
SegTree(int n){
while(size < n)size *= 2;
mins.resize(2 * size);
}
void set(int i, int x, int lx, int rx){
if(rx - lx == 1){
mins[x] = 1;
return;
}
int m = (lx + rx) >> 1;
if(i < m)set(i, 2 * x + 1, lx, m);
else set(i, 2 * x + 2, m, rx);
mins[x] = mins[2 * x + 1] + mins[2 * x + 2];
}
void set(int i){
set(i, 0, 0, size);
}
int sum(int l, int r, int x, int lx, int rx){
if(l <= lx and rx <= r)return mins[x];
if(r <= lx or rx <= l)return 0;
int m = (lx + rx) >> 1;
return sum(l, r, 2 * x + 1, lx, m) + sum(l, r, 2 * x + 2, m, rx);
}
int sum(int l, int r){
return sum(l, r, 0, 0, size);
}
void printtree(){
for(auto x : mins)cout<< x << ' ';
cout<<endl;
}
};
long long count_swaps(vector<int> a) {
long long n = a.size() / 2;
if(n == 1)return a[0] > 0;
vector<vector<int>> pos(2 * n + 1);
for(int i = 2 * n - 1; i >= 0; i --)
pos[a[i] + n].push_back(i);
long long ans = 0;
SegTree s(2 * n);
for(int i = 0; i < 2 * n; i ++){
if(a[i] != 0){
ans += pos[-a[i] + n].back() - i - s.sum(i, pos[-a[i] + n].back());
if(a[i] < 0)ans --;
s.set(pos[-a[i] + n].back());
s.set(i);
a[pos[-a[i] + n].back()] = 0;
pos[-a[i] + n].pop_back();
pos[a[i] + n].pop_back();
a[i] = 0;
}
}
return ans;
}
