#include "seats.h"
#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")
#pragma GCC target("popcnt")
using namespace std;
using ll = long long;
using ull = unsigned long long;
using lld = long double;
using ii = pair<int,int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vll = vector<ll>;
using vii = vector<ii>;
using vpll = vector<pll>;
using vlld = vector<lld>;
#define all(x) x.begin(),x.end()
#define lsb(x) x&(-x)
#define gcd(a,b) __gcd(a,b)
#define sz(x) (int)x.size()
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define fls cout.flush()
#define fore(i, l, r) for (auto i = l; i < r; i++)
#define fo(i, n) fore (i, 0, n)
#define forex(i, r, l) for (auto i = r-1; i >= l; i--)
#define ffo(i, n) forex (i, n, 0)
bool cmin(ll &a, ll b) { if (b < a) { a=b; return 1; } return 0; }
bool cmax(ll &a, ll b) { if (b > a) { a=b; return 1; } return 0; }
void valid(ll in) { cout<<((in)?"YES\n":"NO\n"); }
ll lcm(ll a, ll b) { return (a/gcd(a,b))*b; }
ll gauss(ll n) { return (n*(n+1))/2; }
const ll INF = 1e18;
struct SegTree {
struct Node {
ll mn, cnt;
Node ( ) { }
Node (ll mn, ll cnt): mn(mn), cnt(cnt) { }
Node operator +(const Node &o) {
return {
min(mn, o.mn),
(mn <= o.mn ? cnt : 0) +
(o.mn <= mn ? o.cnt : 0)
};
};
};
Node IDEM = {0, 1};
vector<Node> st;
vll lz;
ll n;
SegTree () { }
SegTree (ll n): st(4*n+4, IDEM), lz(4*n+4,0), n(n) { }
void push (ll id, ll l, ll r) {
st[id].mn += lz[id];
if (l != r) {
lz[id*2] += lz[id];
lz[id*2+1] += lz[id];
}
lz[id] = 0;
}
void update (ll l, ll r, ll c) { update(1, 0, n-1, l, r, c); }
void update (ll id, ll l, ll r, ll i, ll j, ll c) {
push(id, l, r);
if (r < i || j < l) return;
if (i <= l && r <= j) {
lz[id] += c;
push(id, l, r);
return;
}
ll m = (l+r)/2;
update(id*2, l, m, i, j, c);
update(id*2+1, m+1, r, i, j, c);
st[id] = st[id*2] + st[id*2+1];
}
};
const int N = 1e6 + 7;
vector<vll> a;
pll pos[N];
ll h, w;
SegTree st;
ll num (ll i, ll j) { return (0 <= i && i < h && 0 <= j && j < w ? a[i][j] : h*w); }
void upd (ll i, ll j, ll c) {
vll vec;
vec.pb(num(i-1, j-1));
vec.pb(num(i-1, j));
vec.pb(num(i, j-1));
vec.pb(num(i, j));
sort(all(vec));
st.update(vec[0], vec[1]-1, +c);
if (vec[2] < h*w) st.update(vec[2], vec[3]-1, +c);
}
void give_initial_chart(int H, int W, std::vector<int> R, std::vector<int> C) {
h = H;
w = W;
st = SegTree(h*w);
a = vector<vll>(h, vll(w));
fo (i, h*w) a[R[i]][C[i]] = i;
fo (i, h*w) pos[i] = {R[i], C[i]};
fo (i, H+1) {
fo (j, W+1) {
upd(i, j, +1);
}
}
}
int swap_seats(int x, int y) {
ll ix = pos[x].fi, jx = pos[x].se;
ll iy = pos[y].fi, jy = pos[y].se;
set<pll> ds;
ds.insert({ix, jx});
ds.insert({ix+1, jx});
ds.insert({ix, jx+1});
ds.insert({ix+1, jx+1});
ds.insert({iy, jy});
ds.insert({iy+1, jy});
ds.insert({iy, jy+1});
ds.insert({iy+1, jy+1});
for (auto [i, j]: ds) upd(i, j, -1);
swap(a[ix][jx], a[iy][jy]);
swap(pos[x], pos[y]);
for (auto [i, j]: ds) upd(i, j, +1);
auto ans = st.st[1];
return (ans.mn == 4 ? ans.cnt : 0);
}
