Submission #1029177

#	Time	Username	Problem	Language	Result	Execution time	Memory
1029177		marvinthang	Fire (BOI24_fire)	C++17	100 / 100	280 ms	98428 KiB

Main

/*************************************
*    author: marvinthang             *
*    created: 06.05.2024 15:52:23    *
*************************************/

#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

const int LOG = 19;

void process(void) {
	int n, m; cin >> n >> m;
	vector <pair <int, int>> a(n); cin >> a;
	vector <int> c; 
	REP(i, n) {
		c.push_back(a[i].fi);
		c.push_back(a[i].se);
	}
	sort(ALL(c));
	c.erase(unique(ALL(c)), c.end());
	REP(i, n) {
		a[i].fi = lower_bound(ALL(c), a[i].fi) - c.begin();
		a[i].se = lower_bound(ALL(c), a[i].se) - c.begin();
		if (a[i].fi > a[i].se) a[i].se += c.size();
		a.emplace_back(a[i].fi + c.size(), a[i].se + c.size());
	}
	n += n;
	sort(ALL(a));
	vector <array <pair <int, int>, LOG>> ma(n);
	REP(i, n) ma[i][0] = pair{a[i].se, i};
	FOR(k, 1, LOG) REP(i, n - MASK(k) + 1) ma[i][k] = max(ma[i][k - 1], ma[i + MASK(k - 1)][k - 1]);
	auto get_max = [&] (int l, int r) {
		if (l > r) return n;
		int h = __lg(r - l + 1);
		return max(ma[l][h], ma[r - MASK(h) + 1][h]).se;
	};
	vector <array <int, LOG>> nxt(n + 1);
	nxt[n][0] = n;
	REP(i, n) {
		int pos = lower_bound(i + ALL(a), pair{a[i].se + 1, -1}) - a.begin() - 1;
		nxt[i][0] = get_max(i + 1, pos);
	}
	FOR(k, 1, LOG) REP(i, n + 1) nxt[i][k] = nxt[nxt[i][k - 1]][k - 1];
	int res = n + 1;
	REP(i, n / 2) {
		int cur = 0, u = i;
		REPD(j, LOG) if (nxt[u][j] < n && a[nxt[u][j]].se < a[i].fi + c.size()) {
			u = nxt[u][j];
			cur ^= MASK(j);
		}
		if (nxt[u][0] < n) res = min(res, cur + 2);
	}
	cout << (res == n + 1 ? -1 : res) << '\n';
}

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

Compilation message (stderr)

Main.cpp: In function 'void process()':
Main.cpp:83:53: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   83 |   REPD(j, LOG) if (nxt[u][j] < n && a[nxt[u][j]].se < a[i].fi + c.size()) {
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:94:2: note: in expansion of macro 'file'
   94 |  file("fire");
      |  ^~~~
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:94:2: note: in expansion of macro 'file'
   94 |  file("fire");
      |  ^~~~

• Subtask 1: 14 / 14
• Subtask 2: 17 / 17
• Subtask 3: 9 / 9
• Subtask 4: 13 / 13
• Subtask 5: 21 / 21
• Subtask 6: 26 / 26