#include <bits/stdc++.h>
#include "seats.h"
using namespace std;
typedef long long i64;
struct Info {
i64 mi;
int cnt;
};
Info merge(const Info &a, const Info &b) {
if (a.mi < b.mi)
return a;
if (b.mi < a.mi)
return b;
return {a.mi, a.cnt + b.cnt};
}
class SegTree {
vector<Info> arr;
vector<i64> lazy;
int s;
void push(int n, int nb, int ne) {
if (!lazy[n]) return;
arr[n].mi += lazy[n];
if (nb + 1 != ne) {
lazy[2 * n] += lazy[n];
lazy[2 * n + 1] += lazy[n];
}
lazy[n] = 0;
}
void update(int l, int r, i64 d, int n, int nb, int ne) {
push(n, nb, ne);
if (ne <= l || nb >= r) return;
if (l <= nb && ne <= r) {
lazy[n] = d;
push(n, nb, ne);
return;
}
update(l, r, d, 2 * n, nb, (nb + ne) / 2);
update(l, r, d, 2 * n + 1, (nb + ne) / 2, ne);
arr[n] = merge(arr[2 * n], arr[2 * n + 1]);
}
Info query(int l, int r, int n, int nb, int ne) {
push(n, nb, ne);
if (ne <= l || nb >= r) return {(i64)1e18, 1};
if (l <= nb && ne <= r) return arr[n];
return merge(
query(l, r, 2 * n, nb, (nb + ne) / 2),
query(l, r, 2 * n + 1, (nb + ne) / 2, ne));
}
public:
void update(int l, int r, i64 d) { update(l, r, d, 1, 0, s); }
int query(int l, int r) { return query(l, r, 1, 0, s).cnt; }
SegTree() { }
SegTree(int N) {
s = 1 << (int)ceil(log2(N));
arr.resize(2 * s, {0, 1});
lazy.resize(2 * s);
for (int i = s - 1; i > 0; i--)
arr[i] = merge(arr[2 * i], arr[2 * i + 1]);
}
};
#define GOOD_SQUARE_VALUE 1
#define BAD_SQUARE_VALUE ((int)1e7)
int H, W;
vector<vector<int>> grid;
vector<pair<int, int>> pos;
SegTree segtree;
bool get_status(int i, int j, int t) {
if (i < 0 || j < 0 || i >= H || j >= W)
return false;
return grid[i][j] <= t;
}
int get_square_value(int x, int y, int dx, int dy, int t) {
int cnt = get_status(x, y, t) + get_status(x + dx, y, t)
+ get_status(x, y + dy, t) + get_status(x + dx, y + dy, t);
switch (cnt) {
case 1: return GOOD_SQUARE_VALUE;
case 3: return BAD_SQUARE_VALUE;
default: return 0;
}
}
void do_update(int idx, bool rev = false) {
auto [x, y] = pos[idx];
int factor = rev ? -1 : +1;
i64 upd = 0;
// Remove old squares
for (auto dx: {-1, +1})
for (auto dy: {-1, +1})
upd -= get_square_value(x, y, dx, dy, idx - 1) * factor;
// Add new squares
for (auto dx: {-1, +1})
for (auto dy: {-1, +1})
upd += get_square_value(x, y, dx, dy, idx) * factor;
// Push to segment
segtree.update(idx, H * W, upd);
}
void give_initial_chart(int H, int W, vector<int> R, vector<int> C) {
::H = H, ::W = W;
grid.assign(H, vector<int>(W));
pos.resize(H * W);
for (int i = 0; i < H * W; i++) {
pos[i] = {R[i], C[i]};
grid[R[i]][C[i]] = i;
}
segtree = SegTree(H * W);
for (int i = 0; i < H * W; i++) {
do_update(i);
}
}
int swap_seats(int a, int b) {
set<pair<int, int>> to_update;
for (auto c: {a, b})
for (int x = max(0, pos[c].first - 1); x <= min(H - 1, pos[c].first + 1); x++)
for (int y = max(0, pos[c].second - 1); y <= min(W - 1, pos[c].second + 1); y++)
to_update.emplace(x, y);
for (auto [x, y]: to_update)
do_update(grid[x][y], true);
swap(pos[a], pos[b]);
grid[pos[a].first][pos[a].second] = a;
grid[pos[b].first][pos[b].second] = b;
for (auto [x, y]: to_update)
do_update(grid[x][y]);
return segtree.query(0, H * W);
}
