#include <bits/stdc++.h>
//#include "grader.cpp"
#include "ext/pb_ds/assoc_container.hpp"
#include "parks.h"
#define F first
#define S second
#define pb push_back
#define sz(x) (int)x.size()
#define el "\n"
#define all(x) (x).begin(), (x).end()
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("-O3")
#pragma GCC optimize("Ofast")
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
const int N = 5e5 + 500;
mt19937 rnd(time(0));
const int steps[4][2] = {{0, 2}, {2, 0}, {0, -2}, {-2, 0}};
const int dsteps[4][2] = {{1, 1}, {1, -1}, {-1, 1}, {-1, -1}};
map <pair <int, int>, pair <int, int> > road;
pair <int, int> block[N * 2];
int pr[N];
int cmp[2 * N], to[2 * N];
vector <int> g[2 * N], gr[2 * N], ord;
bool mk[2 * N];
int f(int v) {return (pr[v] == v ? v : pr[v] = f(pr[v]));}
void link(int v, int u) {
v = f(v); u = f(u);
if (v == u) {
return;
}
pr[u] = v;
}
int nt(int x) {return (x < N ? x + N : x - N);}
void add_impl(int a, int b) {
int na = nt(a), nb = nt(b);
g[na].pb(b); gr[b].pb(na);
g[nb].pb(a); gr[a].pb(nb);
}
void dfs(int v) {
mk[v] = 1;
for (auto u : g[v]) {
if (mk[u]) {
continue;
}
dfs(u);
}
ord.pb(v);
}
vector <pair <int, int> > pts;
void dfsd(int v) {
mk[v] = 1;
for (auto u : g[v]) {
if (mk[u]) {
continue;
}
int dx = pts[v].F - pts[u].F;
int dy = pts[v].S - pts[u].S;
block[u] = road[{dx, dy}];
dfsd(u);
}
}
inline geth(int a, int b) {return ((ll)a << 32) + b;}
void get_erased_2x2(vector <int> &x, vector <int> &y, gp_hash_table<ll, int> &del) {
gp_hash_table <ll, int> cnt, who;
for (int i = 0; i < sz(x); i++) {
who[geth(x[i], y[i])] = i;
for (int j = 0; j < 4; j++) {
int cx = x[i] + dsteps[j][0];
int cy = y[i] + dsteps[j][1];
cnt[geth(cx, cy)]++;
if (cnt[geth(cx, cy)] == 4) {
pts.pb({cx, cy});
}
}
}
sort(all(pts));
cnt.clear();
int ptr = 0;
for (auto &[x, y] : pts) {
cnt[geth(x, y)] = ptr++;
}
ptr = 0;
for (auto &[x, y] : pts) {
int par = (x / 2 + y / 2) % 2;
for (int i = 0; i < 2; i++) {
int cx = x + steps[i * 2 + par][0];
int cy = y + steps[i * 2 + par][1];
if (cnt.find(geth(cx, cy)) == cnt.end()) {
continue;
}
g[cnt[geth(cx, cy)]].pb(ptr);
}
ptr++;
}
for (int i = 0; i < sz(pts); i++) {
if (mk[i]) {
continue;
}
int par = (pts[i].F / 2 + pts[i].S / 2) & 1;
if (par & 1) {
block[i] = road[{-2, 0}];
} else {
block[i] = road[{0, -2}];
}
queue <int> q;
q.push(i); mk[i] = 1;
while (sz(q)) {
int v = q.front(); q.pop();
for (auto u : g[v]) {
if (mk[u]) {
continue;
}
int dx = pts[v].F - pts[u].F;
int dy = pts[v].S - pts[u].S;
block[u] = road[{dx, dy}];
q.push(u);
mk[u] = 1;
}
}
}
for (int i = 0; i < sz(pts); i++) {
auto [x, y] = pts[i];
auto [a, b] = block[i];
int v = who[geth(x + dsteps[a][0], y + dsteps[a][1])];
int u = who[geth(x + dsteps[b][0], y + dsteps[b][1])];
del[geth(v, u)] = del[geth(u, v)] = 1;
}
}
int construct_roads(vector <int> x, vector <int> y) {
int n = sz(x);
road[{0, 2}] = {2, 0}; road[{2, 0}] = {0, 1};
road[{0, -2}] = {1, 3}; road[{-2, 0}] = {3, 2};
gp_hash_table <ll, int> mp;
vector <pair <int, int> > r;
gp_hash_table <ll, int> del;
vector <int> pm(n);
iota(all(pm), 0);
shuffle(all(pm), rnd);
bool sd = 1;
for (int i = 0; i < n; i++) {
mp[geth(x[i], y[i])] = i;
pr[i] = i;
sd &= (x[i] >= 2 && x[i] <= 4);
}
get_erased_2x2(x, y, del);
for (auto i : pm) {
for (int j = 0; j < 4; j++) {
int cx = x[i] + steps[j][0];
int cy = y[i] + steps[j][1];
if (mp.find(geth(cx, cy)) != mp.end() && f(i) != f(mp[geth(cx, cy)])) {
int to = mp[geth(cx, cy)];
if (del.find(geth(i, to)) != del.end()) {
continue;
}
link(i, to);
r.pb({i, to});
}
}
}
sort(all(r));
r.resize(unique(all(r)) - r.begin());
for (int i = 0; i < n; i++) {
if (f(i) != f(0)) {
return 0;
}
}
vector <int> u, v, A, B;
gp_hash_table <ll, vector <int> > e;
for (int i = 0; i < sz(r); i++) {
int a = r[i].F, b = r[i].S;
u.pb(a); v.pb(b);
if (abs(x[a] - x[b]) == 0) {
int lx = x[a];
int ly = min(y[a], y[b]);
e[geth(lx - 1, ly + 1)].pb(i);
e[geth(lx + 1, ly + 1)].pb(nt(i));
} else {
int lx = min(x[a], x[b]);
int ly = y[a];
e[geth(lx + 1, ly + 1)].pb(i);
e[geth(lx + 1, ly - 1)].pb(nt(i));
}
}
for (int i = 0; i < 2 * N; i++) {
mk[i] = 0;
g[i].clear();
}
for (auto [p, v] : e) {
int x = (p >> 32), y = (p & ((1 << 32) - 1));
if (sz(v) == 1) {
continue;
}
for (auto a : v) {
for (auto b : v) {
if (a == b) {
continue;
}
add_impl(a, b);
}
}
}
for (int i = 0; i < 2 * N; i++) {
cmp[i] = -1;
if (mk[i]) {
continue;
}
dfs(i);
}
reverse(all(ord));
int C = 0;
for (auto v : ord) {
function <void(int)> dfsr = [&](int v) {
if (cmp[v] != -1) {
return;
}
cmp[v] = C;
for (auto u : gr[v]) {
dfsr(u);
}
};
dfsr(v);
C++;
}
for (int i = 0; i < N; i++) {
if (cmp[i] == cmp[nt(i)]) {
return 0;
}
to[i] = (cmp[i] > cmp[nt(i)]);
}
for (int i = 0; i < sz(r); i++) {
int a = r[i].F, b = r[i].S;
if (abs(x[a] - x[b]) == 0) {
int lx = x[a];
int ly = min(y[a], y[b]);
if (to[i]) {
A.pb(lx + 1);
} else {
A.pb(lx - 1);
}
B.pb(ly + 1);
} else {
int lx = min(x[a], x[b]);
int ly = y[a];
if (to[i]) {
B.pb(ly - 1);
} else {
B.pb(ly + 1);
}
A.pb(lx + 1);
}
}
build(u, v, A, B);
return 1;
}
Compilation message
parks.cpp:78:8: error: ISO C++ forbids declaration of 'geth' with no type [-fpermissive]
78 | inline geth(int a, int b) {return ((ll)a << 32) + b;}
| ^~~~
parks.cpp: In function 'int construct_roads(std::vector<int>, std::vector<int>)':
parks.cpp:226:41: warning: left shift count >= width of type [-Wshift-count-overflow]
226 | int x = (p >> 32), y = (p & ((1 << 32) - 1));
| ~~^~~~~
parks.cpp:226:13: warning: unused variable 'x' [-Wunused-variable]
226 | int x = (p >> 32), y = (p & ((1 << 32) - 1));
| ^
parks.cpp:226:28: warning: unused variable 'y' [-Wunused-variable]
226 | int x = (p >> 32), y = (p & ((1 << 32) - 1));
| ^
