#include "shoes.h"
#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 5e5 + 5;
vector<vector<int>> L(MAX_N), R(MAX_N);
bitset<MAX_N> solved;
class FenwickTree {
private:
vector<int> bit;
const int L;
public:
FenwickTree(int n) : L(n + 5) {
bit.clear();
bit.resize(L);
}
void update(int idx, int delta) {
for (; idx < L; idx += idx & (- idx)) {
bit[idx] += delta;
}
}
void range_update(int lo, int hi, int delta) {
++lo; ++hi;
update(lo, +delta);
update(hi + 1, -delta);
}
int query(int idx) {
++idx;
int res = 0;
for (; idx > 0; idx -= idx & (- idx)) {
res += bit[idx];
}
return res;
}
};
long long count_swaps(vector<int> s) {
const int n = s.size();
for (int i = 0; i < n; i++) {
const int cur = abs(s[i]);
if (s[i] < 0) {
L[cur].emplace_back(i);
} else {
R[cur].emplace_back(i);
}
}
for (int i = 0; i < MAX_N; i++) {
reverse(L[i].begin(), L[i].end());
reverse(R[i].begin(), R[i].end());
}
FenwickTree fen(n);
auto get_idx = [&](int idx) {
return idx + fen.query(idx);
};
long long res = 0;
for (int i = 0; i < n; i++) {
if (solved[i]) continue;
const int cur = abs(s[i]);
int lo = i;
int hi;
if (s[i] > 0) {
R[cur].pop_back();
hi = L[cur].back();
L[cur].pop_back();
} else {
L[cur].pop_back();
hi = R[cur].back();
R[cur].pop_back();
}
solved[lo] = solved[hi] = 1;
res += (s[i] > 0) + get_idx(hi) - get_idx(lo) - 1;
fen.range_update(lo, hi, + 1);
}
return res;
}
