#include "seats.h"
#include<bits/stdc++.h>
using namespace std;
const int N = 1000005;
int n, m, k;
int posx[N], posy[N];
int num[N];
int minv[2100000], minc[2100000], lazy[2100000]; // initial values are 0, thus, minv is 0 for every val;
int a[5];
void build(int id, int l, int r);
int get(int x, int y);
void supd(int id, int l, int r, int ll, int rr, int val);
void upd(int x, int y, int v);
void change(int x, int y, int v);
void give_initial_chart(int H, int W, std::vector<int> R, std::vector<int> C) {
n = H;
m = W;
k = H * W;
build(1, 0, k - 1); // initially every val is 0;
for (int i = 0; i < k ; i++) {
posy[i] = R[i];
posx[i] = C[i];
num[posy[i]*m+posx[i]]=i;
}
for (int i = 0; i <= n; i++) {
for (int j = 0; j <= m; j++) {
upd(j, i, 1);
}
}
}
int swap_seats(int a, int b) {
change(posx[a], posy[a], b);
change(posx[b], posy[b], a);
swap(posx[a], posx[b]);
swap(posy[a], posy[b]);
return minc[1];
}
void change(int x, int y, int v) {
for (int i = 0; i < 2; i++) {
for (int j = 0; j < 2; j++) {
upd(x+i, y+j, -1);
}
}
num[y * m + x] = v;
for (int i = 0; i < 2; i++) {
for (int j = 0; j < 2; j++) {
upd(x+i, y+j, 1);
}
}
}
void build(int id, int l, int r) {
minc[id] = r - l + 1;
if (r == l) return;
int mid = (l + r) / 2;
build(2 * id, l, mid);
build(2 * id + 1, mid + 1, r);
}
int get(int x, int y) {
if (x < 0 || x >= m || y < 0 || y >= n) return k;
return num[y * m + x];
}
void supd(int id, int l, int r, int ll, int rr, int v) {
if (l > rr || r < ll) return;
if (ll <= l && r <= rr) {
lazy[id] += v;
minv[id] += v;
return;
}
int mid = (l + r) / 2;
supd(2*id, l, mid, ll, rr, v);
supd(2*id + 1, mid + 1, r, ll, rr, v);
if (minv[2*id] > minv[2*id+1]) {
minv[id] = minv[2*id+1];
minc[id] = minc[2*id+1];
}
if (minv[2*id] < minv[2*id+1]) {
minv[id] = minv[2*id];
minc[id] = minc[2*id];
}
if (minv[2*id] == minv[2*id + 1]) {
minv[id] = minv[2*id];
minc[id] = minc[2*id] + minc[2*id + 1];
}
minv[id] += lazy[id];
}
void upd(int x, int y, int v) {
for (int i = 0; i < 2; i++) {
for (int j = 0; j < 2; j++) {
a[2 * i + j] = get(x - i, y - j);
}
}
sort (a, a + 4);
if (a[0] < a[1]) supd(1, 0, k - 1, a[0], a[1] - 1, v);
if (a[2] < a[3]) supd(1, 0, k - 1, a[2], a[3] - 1, v);
}
