#include "seats.h"
#include "bits/stdc++.h"
#define rep(i, n) for(ll i = 0; i < ll(n); ++i)
#define rep2(i, s, n) for(ll i = ll(s); i < ll(n); ++i)
#define rrep(i, n) for(ll i = ll(n)-1; i >= 0; --i)
#define pb push_back
#define eb emplace_back
#define all(a) a.begin(),a.end()
#define SZ(a) int(a.size())
using namespace std;
using ll = long long;
using P = pair<int, int>;
using vi = vector<int>;
using vvi = vector<vi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vp = vector<P>;
using vvp = vector<vp>;
using vs = vector<string>;
const int inf = 1001001001;
const ll linf = 1001001001001001001;
template<class T>
bool chmin(T &a, T b) {
if (a > b) {
a = b;
return true;
} else {
return false;
}
}
template<class T>
bool chmax(T &a, T b) {
if (a < b) {
a = b;
return true;
} else {
return false;
}
}
template<class T, class S>
ostream &operator<<(ostream &os, const pair<T, S> &p) {
os << '{' << p.first << ", " << p.second << '}';
return os;
}
using S = P;
const S e = {inf, 0};
S op(S a, S b) {
if (a.first != b.first) return (a.first < b.first ? a : b);
return {a.first, a.second + b.second};
}
using F = int;
const F id = 0;
F composition(F g, F f) { return g + f; }
S mapping(F f, S x) { return {x.first + f, x.second}; }
class lazy_segtree {
int n, log;
vector<S> d;
vector<F> lz;
void all_apply(int p, F f) {
d[p] = mapping(f, d[p]);
if (p < n) lz[p] = composition(f, lz[p]);
}
void push(int p) {
assert(p < n);
all_apply(2 * p, lz[p]);
all_apply(2 * p + 1, lz[p]);
lz[p] = id;
}
void update(int p) {
assert(p < n);
d[p] = op(d[2 * p], d[2 * p + 1]);
}
public:
lazy_segtree(const vector<S> &init = {}) {
log = 0;
while (1 << log < SZ(init)) ++log;
n = 1 << log;
d.assign(2 * n, e);
rep(i, SZ(init)) d[n + i] = init[i];
for (int i = n - 1; i >= 1; --i) update(i);
lz.assign(n, id);
}
S get(int p) {
assert(0 <= p and p < n);
p += n;
for (int i = log; i >= 1; --i) push(p >> i);
return d[p];
}
S all_prod() { return d[1]; }
void apply(int l, int r, F f) {
assert(0 <= l and l <= r and r <= n);
l += n, r += n;
for (int i = log; i >= 1; --i) {
if (l >> i << i != l) push(l >> i);
if (r >> i << i != r) push(r >> i);
}
{
int l2 = l, r2 = r;
while (l < r) {
if (l & 1) all_apply(l++, f);
if (r & 1) all_apply(--r, f);
l >>= 1, r >>= 1;
}
l = l2, r = r2;
}
for (int i = 1; i <= log; ++i) {
if (l >> i << i != l) update(l >> i);
if (r >> i << i != r) update(r >> i);
}
}
};
int h, w;
vi r, c;
vvi who;
lazy_segtree st;
void corner_set(int i, int j, int inv = 1) {
assert(0 <= i and i <= h);
assert(0 <= j and j <= w);
// {time, pos}
vector<P> v;
rep2(ni, i - 1, i + 1) rep2(nj, j - 1, j + 1) {
if (ni < 0 or ni >= h or nj < 0 or nj >= w) continue;
v.eb(who[ni][nj], (ni - i + 1) * 2 + (nj - j + 1));
}
v.eb(h * w, -1);
sort(all(v));
if (SZ(v) >= 2) {
st.apply(v[0].first, v[1].first, inv);
}
if (SZ(v) >= 3 and v[0].second + v[1].second == 3) {
st.apply(v[1].first, v[2].first, inv * 2);
}
if (SZ(v) >= 4) {
st.apply(v[2].first, v[3].first, inv);
}
}
void give_initial_chart(int H, int W, vi R, vi C) {
h = H;
w = W;
r = R;
c = C;
who.resize(h);
rep(i, h) who[i].resize(w);
rep(i, h * w) who[r[i]][c[i]] = i;
st = lazy_segtree(vp(h * w, {0, 1}));
rep2(i, 0, h + 1) rep2(j, 0, w + 1) corner_set(i, j);
// rep(i, h * w) cerr << i << ' ' << st.get(i) << endl;
}
int swap_seats(int a, int b) {
set<P> upd;
rep(i, 2) rep(j, 2) upd.insert({r[a] + i, c[a] + j});
rep(i, 2) rep(j, 2) upd.insert({r[b] + i, c[b] + j});
for (auto[i, j]: upd) corner_set(i, j, -1);
swap(r[a], r[b]);
swap(c[a], c[b]);
swap(who[r[a]][c[a]], who[r[b]][c[b]]);
assert(who[r[a]][c[a]] == a);
assert(who[r[b]][c[b]] == b);
for (auto[i, j]: upd) corner_set(i, j);
// rep(i, h * w) cerr << i << ' ' << st.get(i) << endl;
auto[mn, num] = st.all_prod();
// cerr << mn << ' ' << num << endl;
assert(mn >= 4 and (~mn & 1));
return (mn == 4 ? num : 0);
}
