#include "shoes.h"
#include <bits/stdc++.h>
#define mid ((tl + tr) >> 1)
#define lc (node + 1)
#define rc (node + 2 * (mid - tl + 1))
using namespace std;
const int MAXN = 1e5 + 5;
vector<int> pos[2 * MAXN];
bool processed[2 * MAXN];
struct node {
	long long sm, lazy;
};
struct SegmentTree {
	vector<node> tree; 
	void init(int n) {
		tree.resize(2 * n);
	}
	void propagate(int tl, int tr, int node) {
		tree[node].sm += tree[node].lazy * (tr - tl + 1);
		if (tl != tr) {
			tree[lc].lazy += tree[node].lazy;
			tree[rc].lazy += tree[node].lazy;
		}
		tree[node].lazy = 0;
	}
	void update(int tl, int tr, int node, int l, int r, long long val) {
		propagate(tl, tr, node);
		if (tl > r || tr < l) return;
		if (l <= tl && tr <= r) {
			tree[node].lazy += val;
			propagate(tl, tr, node);
			return;
		}
		update(tl, mid, lc, l, r, val), update(mid + 1, tr, rc, l, r, val);
		tree[node].sm = tree[lc].sm + tree[rc].sm;
	}
	long long query(int tl, int tr, int node, int l, int r) {
		propagate(tl, tr, node);
		if (tl > r || tr < l) return 0;
		if (tl >= l && tr <= r) return tree[node].sm;
		return query(tl, mid, lc, l, r) + query(mid + 1, tr, rc, l, r);
	}
};

long long count_swaps(std::vector<int> s) {
	int n = s.size();
	SegmentTree st;
	st.init(2 * MAXN);	
	const int DELTA = MAXN - 3;
	for (int i = n; i; --i)
		pos[s[i - 1] + DELTA].push_back(i);	
	long long ret = 0;
	for (int i = 1; i <= n; ++i) {
		if (processed[i]) continue;
		long long a = pos[s[i - 1] + DELTA].back(), b = pos[DELTA - s[i - 1]].back();
		pos[s[i - 1] + DELTA].pop_back();
		pos[DELTA - s[i - 1]].pop_back();
		processed[a] = processed[b] = true;
		long long x = a + st.query(1, n, 1, a, a), y = b + st.query(1, n, 1, b, b);
		if (s[i - 1] < 0) 
			ret += y - x - 1;
		else 
			ret += y - x;

		if (a + 1 <= b - 1) 
			st.update(1, n, 1, a + 1, b - 1, 1);

	}
	return ret;
}