#include "shoes.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
uint64_t hash_vec(const vector<int> &inp) {
const uint64_t BASE = 998244353;
uint64_t h = 0;
for (int x : inp) {
h = h * BASE + (uint32_t)x + 1;
}
return h;
}
int n;
struct State {
vector<pair<int, int>> swaps;
vector<int> arr;
int moves;
int p1, p2;
};
bool check_valid(State &state, vector<int> &initial) {
vector<int> arrangement = initial;
for (auto &el : state.swaps) {
swap(arrangement[el.first], arrangement[el.second]);
}
bool valid = true;
for (int i = 0; i < n; i++) {
valid = valid && (abs(arrangement[2*i]) == abs(arrangement[2*i+1])) && (arrangement[2*i] < 0 && arrangement[2*i+1] > 0);
}
return valid;
}
bool check_valid(vector<int> &arrangement) {
bool valid = true;
for (int i = 0; i < n; i++) {
valid = valid && (abs(arrangement[2*i]) == abs(arrangement[2*i+1])) && (arrangement[2*i] < 0 && arrangement[2*i+1] > 0);
}
return valid;
}
// left shoe if s[i] < 0
// right shoe if s[i] > 0
ll count_swaps(vector<int> s) {
n = s.size() / 2;
int minimum = 0;
queue<State> q;
State best;
q.push(State{{}, s, 0, -1, -1});
unordered_set<uint64_t> vis;
vis.insert(hash_vec(s));
while (!q.empty()) {
State cur = q.front();
q.pop();
// if (check_valid(cur, s)) {
if (check_valid(cur.arr)) {
minimum = cur.moves;
best = cur;
break;
}
for (int i = 1; i < 2*n; i++) {
for (int j = i-1; j < i+2 && j < 2*n; j++) {
if (i == j) continue;
if (((i == cur.p1) && (j == cur.p2)) || ((j == cur.p1) && (i == cur.p2))) continue;
// vector<pair<int, int>> swaps = cur.swaps;
// swaps.push_back({i, j});
// q.push(State{swaps, cur.moves + 1, i, j});
vector<int> cs = cur.arr;
swap(cs[i], cs[j]);
uint64_t h = hash_vec(cs);
if (vis.count(h)) continue;
vis.insert(h);
q.push(State{{}, cs, cur.moves + 1, i, j});
}
}
}
// cout << "Fastest fix is " << best.moves << " moves\n";
// for (auto &el : best.swaps) {
// cout << "Swapped " << el.first << " and " << el.second << "\n";
// }
return minimum;
// return ll(n) * ll(n - 1) / 2LL;
}
