Submission #1029179

#	Time	Username	Problem	Language	Result	Execution time	Memory
1029179		marvinthang	Tiles (BOI24_tiles)	C++17	100 / 100	102 ms	10804 KiB

Main

/*************************************
*    author: marvinthang             *
*    created: 06.05.2024 17:49:38    *
*************************************/

#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-- > 0; )
#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 << '}'; }

// end of template

void process(void) {
	int n, m; cin >> n >> m;
	vector <pair <int, int>> points(n); cin >> points;
	points.push_back(points[0]);
	vector <tuple <int, int, int>> segs;
	REP(i, n) {
		if (points[i].fi == points[i + 1].fi) segs.emplace_back(points[i].fi, min(points[i].se, points[i + 1].se), max(points[i].se, points[i + 1].se));
	}
	sort(ALL(segs));
	vector <map <int, int>> mp(2);
	int res = 0;
	int cnt_odd = 0;
	REP(i, segs.size()) {
		auto [x, tl, tr] = segs[i];
		auto Cut = [&] (int p, int v) {
			auto it = mp[p].upper_bound(v);
			if (it != mp[p].begin()) {
				--it;
				if (v <= it->se) {
					auto [l, r] = *it;
					if (v == l || v == r) return;
					cnt_odd -= (r - l) & 1;
					cnt_odd += (v - l) & 1;
					cnt_odd += (r - v) & 1;
					mp[p][l] = v;
					mp[p][v] = r;
				}
			}
		};
		REP(p, 2) {
			int l = tl, r = tr;
			Cut(p, l); Cut(p, r);
			auto it = mp[p].lower_bound(l);
			if (it != mp[p].end() && it->fi < r) {
				if (p != (x & 1)) return void(cout << res << '\n');
				while (it != mp[p].end() && it->fi < r) {
					cnt_odd -= (it->se - it->fi) & 1;
					it = mp[p].erase(it);
				}
			} else if (p == (x & 1)) {
				while (it != mp[p].begin() && prev(it)->se == l) {
					l = prev(it)->fi;
					cnt_odd -= (prev(it)->se - prev(it)->fi) & 1;
					mp[p].erase(prev(it));
				}
				while (it != mp[p].end() && it->fi == r) {
					r = it->se;
					cnt_odd -= (it->se - it->fi) & 1;
					it = mp[p].erase(it);
				}
				cnt_odd += (r - l) & 1;
				mp[p][l] = r;
			}
		}
		if (i + 1 < (int) segs.size() && x != get<0>(segs[i + 1])) {
			if (cnt_odd) break;
			x = get<0>(segs[i + 1]);
			if (mp[0].empty()) res = max(res, x - !(x & 1));
			if (mp[1].empty()) res = max(res, x - (x & 1));
		}
	}
	cout << res << '\n';
}

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

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.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); }
      |                                                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:111:2: note: in expansion of macro 'file'
  111 |  file("tiles");
      |  ^~~~
Main.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); }
      |                                                                                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:111:2: note: in expansion of macro 'file'
  111 |  file("tiles");
      |  ^~~~

• Subtask 1: 4 / 4
• Subtask 2: 9 / 9
• Subtask 3: 11 / 11
• Subtask 4: 19 / 19
• Subtask 5: 22 / 22
• Subtask 6: 25 / 25
• Subtask 7: 10 / 10