#include "seats.h"
#include <bits/stdc++.h>
using namespace std;
int H, W;
vector<int> R, C;
struct seg {
int min, ans;
} tree[4 * 1000 * 1000];
vector<int> rev;
int lazy[4 * 1000 * 1000];
seg merge(seg a, seg b) {
if (a.min < b.min) {
return a;
} else if(b.min < a.min) {
return b;
} else {
return {a.min, a.ans + b.ans};
}
}
seg build(int cur, int lo, int hi) {
if (lo == hi) {
return tree[cur] = {0, 1};
}
int lmid = (lo + hi) / 2, rmid = lmid + 1;
return merge(build(cur << 1 | 0, lo, lmid),
build(cur << 1 | 1, rmid, hi));
}
void update(int l, int r, int delta, int cur, int lo, int hi) {
if (lo == l && hi == r) {
lazy[cur] += delta;
tree[cur].min += delta;
} else {
lazy[cur << 1 | 0] += lazy[cur];
tree[cur << 1 | 0].min += lazy[cur];
lazy[cur << 1 | 1] += lazy[cur];
tree[cur << 1 | 1].min += lazy[cur];
lazy[cur] = 0;
int lmid = (lo + hi) / 2, rmid = lmid + 1;
if (l <= lmid) {
update(l, min(r, lmid), delta, cur << 1 | 0, lo, lmid);
}
if (r >= rmid) {
update(max(l, rmid), r, delta, cur << 1 | 1, rmid, hi);
}
tree[cur] = merge(tree[cur << 1 | 0],
tree[cur << 1 | 1]);
}
}
void update(int l, int r, int delta) {
update(l + 1, r, delta, 1, 1, H * W);
}
void give_initial_chart(int HH, int WW, vector<int> RR, vector<int> CC) {
H = HH, W = WW, R = RR, rev = CC;
C.resize(H * W + 2);
C[0] = H * W;
for (int i = 0; i < H * W; i++) {
C[rev[i] + 1] = i;
}
C[H * W + 1] = H * W;
build(1, 1, H * W);
for (int i = 0; i <= H * W; i++) {
update(min(C[i], C[i + 1]), max(C[i], C[i + 1]), +1);
}
}
int swap_seats(int a, int b) {
int ta = a, tb = b;
a = rev[a] + 1, b = rev[b] + 1;
update(min(C[a], C[a - 1]), max(C[a], C[a - 1]), -1);
update(min(C[a], C[a + 1]), max(C[a], C[a + 1]), -1);
update(min(C[b], C[b - 1]), max(C[b], C[b - 1]), -1);
update(min(C[b], C[b + 1]), max(C[b], C[b + 1]), -1);
swap(C[a], C[b]);
swap(rev[ta], rev[tb]);
update(min(C[a], C[a - 1]), max(C[a], C[a - 1]), +1);
update(min(C[a], C[a + 1]), max(C[a], C[a + 1]), +1);
update(min(C[b], C[b - 1]), max(C[b], C[b - 1]), +1);
update(min(C[b], C[b + 1]), max(C[b], C[b + 1]), +1);
return tree[1].min == 2? tree[1].ans : 0;
}
