Submission #777497

#	Time	Username	Problem	Language	Result	Execution time	Memory
777497		marvinthang	IOI Fever (JOI21_fever)	C++17	37 / 100	5082 ms	25792 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 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;
}

void process(void) {
	int res = 0;
	// REP(i, 4) REP(j, 4) {
	// 	dir[0] = i;
	// 	dir[1] = j;
	// 	if (inter(0, 1)) cout << i << ' ' << j << '\n';
	// }
	REP(fl, 2) {
		REP(rt, 2) {
			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;
				}
			}
			vector <bool> visited(N);
			priority_queue <pair <int, int>, vector <pair <int, int>>, greater <pair <int, int>>> q;
			q.emplace(0, 0);
			int cnt = 0;
			while (!q.empty()) {
				auto [t, u] = q.top(); q.pop();
				if (visited[u]) continue;
				visited[u] = true;
				// cout << u << '\n';
				++cnt;
				REP(v, N) if (!visited[v] && inter(u, v)) {
					int d = abs(X[u] - X[v]) + abs(Y[u] - Y[v]);
					if (d < t) continue;
					// cout << u << ' ' << v << '\n';
					q.emplace(d, v);
					// visited[v] = true;
				}
			}
			// cout << '\n';
			maximize(res, cnt);
			REP(i, N) X[i] = -X[i];
			// cout << "---------\n";
		}
		REP(i, N) swap(X[i], Y[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 '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:126:2: note: in expansion of macro 'file'
  126 |  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:126:2: note: in expansion of macro 'file'
  126 |  file("fever");
      |  ^~~~

• 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