Submission #777619

#	Time	Username	Problem	Language	Result	Execution time	Memory
777619		marvinthang	IOI Fever (JOI21_fever)	C++17	37 / 100	5055 ms	236324 KiB

fever

/*************************************
*    author: marvinthang             *
*    created: 09.07.2023 15:47:28    *
*************************************/

#include <bits/stdc++.h>

using namespace std;

#define                  fi  first
#define                  se  second
#define                left  ___left
#define               right  ___right
#define                TIME  (1.0 * clock() / CLOCKS_PER_SEC)
#define             MASK(i)  (1LL << (i))
#define           BIT(x, i)  ((x) >> (i) & 1)
#define  __builtin_popcount  __builtin_popcountll
#define              ALL(v)  (v).begin(), (v).end()
#define           REP(i, n)  for (int i = 0, _n = (n); i < _n; ++i)
#define          REPD(i, n)  for (int i = (n); i--; )
#define        FOR(i, a, b)  for (int i = (a), _b = (b); i < _b; ++i) 
#define       FORD(i, b, a)  for (int i = (b), _a = (a); --i >= _a; ) 
#define       FORE(i, a, b)  for (int i = (a), _b = (b); i <= _b; ++i) 
#define      FORDE(i, b, a)  for (int i = (b), _a = (a); i >= _a; --i) 
#define        scan_op(...)  istream & operator >> (istream &in, __VA_ARGS__ &u)
#define       print_op(...)  ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
    #include "debug.h"
#else
    #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
    #define DB(...) 23
    #define db(...) 23
    #define debug(...) 23
#endif

template <class U, class V> scan_op(pair <U, V>)  { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>)  { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>)  { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")";  else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }
template <class A, class B> bool minimize(A &a, B b)  { if (a > b) { a = b; return true; } return false; }
template <class A, class B> bool maximize(A &a, B b)  { if (a < b) { a = b; return true; } return false; }

// end of template

const long long INF = 1e18;
const int MAX = 1e5 + 5;

int N, X[MAX], Y[MAX];

void init(void) {
	cin >> N;
	REP(i, N) cin >> X[i] >> Y[i];
	REPD(i, N) X[i] -= X[0], Y[i] -= Y[0];
}

int dir[MAX];

bool inter(int u, int v) {
	if (dir[u] == dir[v]) return false;
	if ((dir[u] ^ dir[v]) == 2) {
		if (BIT(dir[u], 0)) {
			if (Y[u] != Y[v]) return false;
			return dir[u] == 1 ? X[u] <= X[v] : X[u] >= X[v];
		}
		if (X[u] != X[v]) return false;
		return dir[u] ? Y[u] >= Y[v] : Y[u] <= Y[v];
	}
	if ((dir[u] ^ dir[v]) == 1) {
		if (X[u] + Y[u] != X[v] + Y[v]) return false;
		return X[u] > X[v] ? dir[u] == 0 || dir[u] == 3 : dir[v] == 0 || dir[v] == 3;
	}
	if (X[u] - Y[u] != X[v] - Y[v]) return false;
	return X[u] > X[v] ? dir[u] == 2 || dir[u] == 3 : dir[v] == 2 || dir[v] == 3;
}

long long dist[MAX][3];
bool visited[MAX];

vector <pair <int, int>> tadj[MAX][3];

int get_dist(int x, int y) {
	return abs(X[x] - X[y]) + abs(Y[x] - Y[y]);
}

void process(void) {
	int res = 0;
	REP(rt, 4) {
		dir[0] = 1;
		FOR(i, 1, N) {
			if (X[i] >= 0) {
				if (Y[i] >= 0) dir[i] = X[i] <= Y[i] ? 2 : 3;
				else dir[i] = X[i] <= -Y[i] ? 0 : 3;
			} else {
				if (Y[i] >= 0) dir[i] = -X[i] < Y[i] ? 2 : 1;
				else dir[i] = -X[i] < -Y[i] ? 0 : 1;
			}
		}
		map <int, set <pair <int, int>>> sum[4], diff[4], sx[4], sy[4];

		REP(i, N) {
			REP(j, 12) {
				dist[i][j] = INF;
				tadj[i][j].clear();
			}
			visited[i] = false;
			sum[dir[i]][X[i] + Y[i]].emplace(X[i], i);
			diff[dir[i]][X[i] - Y[i]].emplace(X[i], i);
			sx[dir[i]][X[i]].emplace(Y[i], i);
			sy[dir[i]][Y[i]].emplace(X[i], i);
			REP(d, 4) {
				sum[d][X[i] + Y[i]].emplace(-1e9, -1);
				sum[d][X[i] + Y[i]].emplace(1e9, -1);
				diff[d][X[i] - Y[i]].emplace(-1e9, -1);
				diff[d][X[i] - Y[i]].emplace(1e9, -1);
				sx[d][X[i]].emplace(-1e9, -1);
				sx[d][X[i]].emplace(1e9, -1);
				sy[d][Y[i]].emplace(-1e9, -1);
				sy[d][Y[i]].emplace(1e9, -1);
			}
		}
		REP(i, N) {
			int sdir = dir[i] ^ 1;
			int ddir = dir[i] ^ 3;
			int odir = dir[i] ^ 2;
			int s = X[i] + Y[i];
			int d = X[i] - Y[i];

			auto it = sum[dir[i]][s].find(make_pair(X[i], i));
			if (dir[i] == 0 || dir[i] == 3) it = next(it);
			else it = prev(it);
			int v = it->se;
			if (v != -1) tadj[i][0].emplace_back(get_dist(i, v), v);

			it = diff[dir[i]][d].find(make_pair(X[i], i));
			if (dir[i] == 2 || dir[i] == 3) it = next(it);
			else it = prev(it);
			v = it->se;
			if (v != -1) tadj[i][1].emplace_back(get_dist(i, v), v);

			if (!BIT(dir[i], 0)) {
				it = sx[dir[i]][X[i]].find(make_pair(Y[i], i));
				if (dir[i] == 2) it = next(it);
				else it = prev(it);
			} else {
				it = sy[dir[i]][Y[i]].find(make_pair(X[i], i));
				if (dir[i] == 3) it = next(it);
				else it = prev(it);
			}
			v = it->se;
			if (v != -1) tadj[i][2].emplace_back(get_dist(i, v), v);
		}

		priority_queue <tuple <long long, int, int>, vector <tuple <long long, int, int>>, greater <tuple <long long, int, int>>> pq;
		pq.emplace(0, 0, -1);

		int cnt = 0;
		while (!pq.empty()) {
			auto [du, u, t] = pq.top(); pq.pop();
			if (t != -1) {
				if (dist[u][t] != du) continue;
				for (auto [w, v]: tadj[u][t]) if (minimize(dist[v][t], du + w)) pq.emplace(dist[v][t], v, t);
			}
			if (visited[u]) continue;
			visited[u] = true;

			vector <tuple <int, int, int>> adj;
			int sdir = dir[u] ^ 1;
			int ddir = dir[u] ^ 3;
			int odir = dir[u] ^ 2;
			int s = X[u] + Y[u];
			int d = X[u] - Y[u];
			sum[dir[u]][X[u] + Y[u]].erase(make_pair(X[u], u));
			diff[dir[u]][X[u] - Y[u]].erase(make_pair(X[u], u));
			sx[dir[u]][X[u]].erase(make_pair(Y[u], u));
			sy[dir[u]][Y[u]].erase(make_pair(X[u], u));

			set<pair <int, int>>::iterator it;

			if (dir[u] == 0 || dir[u] == 3) it = prev(sum[sdir][s].lower_bound(make_pair(X[u] - du / 2, -1)));
			else it = sum[sdir][s].lower_bound(make_pair(X[u] + (du + 1) / 2, -1));
			int v = it->se;
			if (v != -1) adj.emplace_back(0, get_dist(u, v), v);

			it = diff[ddir][d].lower_bound(make_pair(X[u], -1));
			if (dir[u] == 2 || dir[u] == 3) it = prev(diff[ddir][d].lower_bound(make_pair(X[u] - du / 2, -1)));
			else it = diff[ddir][d].lower_bound(make_pair(X[u] + (du + 1) / 2, -1));
			v = it->se;
			if (v != -1) adj.emplace_back(1, get_dist(u, v), v);

			if (!BIT(dir[u], 0)) {
				if (dir[u] == 2) it = prev(sx[odir][X[u]].lower_bound(make_pair(Y[u] - du, N)));
				else it = sx[odir][X[u]].lower_bound(make_pair(Y[u] + du, -1));
			} else {
				if (dir[u] == 3) it = prev(sy[odir][Y[u]].lower_bound(make_pair(X[u] - du, N)));
				else it = sy[odir][Y[u]].lower_bound(make_pair(X[u] + du, -1));
			}
			v = it->se;
			if (v != -1) adj.emplace_back(2, get_dist(u, v), v);
			
			for (auto [t, w, v]: adj) if (w >= du && minimize(dist[v][t], w)) pq.emplace(dist[v][t], v, t);
			++cnt;
		}
		maximize(res, cnt);
		REP(i, N) {
			swap(X[i], Y[i]);
			X[i] = -X[i];
		}
	}
	cout << res << '\n';
}

int main(void) {
	ios_base::sync_with_stdio(false); cin.tie(nullptr); // cout.tie(nullptr);
	file("fever");
	init();
	process();
	cerr << "Time elapsed: " << TIME << " s.\n";
	return (0^0);
}

Compilation message (stderr)

fever.cpp: In function 'void process()':
fever.cpp:124:8: warning: unused variable 'sdir' [-Wunused-variable]
  124 |    int sdir = dir[i] ^ 1;
      |        ^~~~
fever.cpp:125:8: warning: unused variable 'ddir' [-Wunused-variable]
  125 |    int ddir = dir[i] ^ 3;
      |        ^~~~
fever.cpp:126:8: warning: unused variable 'odir' [-Wunused-variable]
  126 |    int odir = dir[i] ^ 2;
      |        ^~~~
fever.cpp: In function 'int main()':
fever.cpp:30:61: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
fever.cpp:216:2: note: in expansion of macro 'file'
  216 |  file("fever");
      |  ^~~~
fever.cpp:30:94: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                                                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
fever.cpp:216:2: note: in expansion of macro 'file'
  216 |  file("fever");
      |  ^~~~
fever.cpp: In function 'void process()':
fever.cpp:104:16: warning: iteration 3 invokes undefined behavior [-Waggressive-loop-optimizations]
  104 |     dist[i][j] = INF;
      |     ~~~~~~~~~~~^~~~~
fever.cpp:19:58: note: within this loop
   19 | #define           REP(i, n)  for (int i = 0, _n = (n); i < _n; ++i)
      |                                                          ^
fever.cpp:103:4: note: in expansion of macro 'REP'
  103 |    REP(j, 12) {
      |    ^~~

• Subtask 1: 5 / 5
• Subtask 2: 8 / 8
• Subtask 3: 6 / 6
• Subtask 4: 6 / 6
• Subtask 5: 12 / 12
• Subtask 6: 0 / 32
• Subtask 7: 0 / 31