#include "seats.h"
#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
const int xx[] = {0, -1, -1, -1, 0, 1, 1, 1, 0};
const int yy[] = {-1, -1, 0, 1, 1, 1, 0, -1, -1};
int H, W;
vector<int> R, C;
vector<vector<int>> S;
pii s1[1<<21], s2[1<<21];
int ss[1<<21];
void upd(int i, int s, int e, int t, pii p) {
if (s==e) {
s1[i]=s2[i]=p;
ss[i]=1;
return ;
}
int m=(s+e)/2;
if (t<=m) upd(i*2, s, m, t, p);
else upd(i*2+1, m+1, e, t, p);
s1[i]=pii(s1[i*2].first+s1[i*2+1].first, s1[i*2].second+s1[i*2+1].second);
pii pp(s1[i*2].first+s2[i*2+1].first, s1[i*2].second+s2[i*2+1].second);
tie(s2[i], ss[i])=min(tie(s2[i*2], ss[i*2]), tie(pp, ss[i*2+1]));
if (s2[i*2]==pp) ss[i]+=max(ss[i*2], ss[i*2+1]);
}
bool av(int x, int y) { return 0<=x&&x<=H-1&&0<=y&&y<=W-1; }
void upd(int x, int y) {
int c=0, d=0;
for (int i=1; i<=7; i+=2) {
int cc=0;
for (int j=-1; j<=1; j++)
if (av(x+xx[i+j], y+yy[i+j])
&&S[x+xx[i+j]][y+yy[i+j]]<S[x][y]) cc++;
if (cc==0) c++;
if (cc==1) {
if (av(x+xx[i], y+yy[i])
&&S[x+xx[i]][y+yy[i]]<S[x][y]) c++;
else c--;
}
if (cc==2) {
if (S[x+xx[i]][y+yy[i]]>S[x][y]) c-=2;
d++;
}
if (cc==3) d--;
}
upd(1, 0, H*W-1, S[x][y], pii(c, d));
}
void give_initial_chart(int H, int W, vector<int> R, vector<int> C) {
::H=H;
::W=W;
::R=R;
::C=C;
S.resize(H, vector<int>(W, 1e9));
for (int i=0; i<H*W; i++) {
S[R[i]][C[i]]=i;
upd(R[i], C[i]);
}
}
int swap_seats(int a, int b) {
swap(R[a], R[b]);
swap(C[a], C[b]);
swap(S[R[a]][C[a]], S[R[b]][C[b]]);
vector<pii> U;
U.emplace_back(R[a], C[a]);
U.emplace_back(R[b], C[b]);
for (int i=0; i<=7; i++) {
if (av(R[a]+xx[i], C[a]+yy[i])) U.emplace_back(R[a]+xx[i], C[a]+yy[i]);
if (av(R[b]+xx[i], C[b]+yy[i])) U.emplace_back(R[b]+xx[i], C[b]+yy[i]);
}
sort(U.begin(), U.end(), [&](pii &p1, pii &p2) {
return S[p1.first][p1.second]<S[p2.first][p2.second];
});
U.resize(unique(U.begin(), U.end())-U.begin());
for (auto &i:U) upd(i.first, i.second);
return ss[1];
}
