Submission #1300568

#	Time	Username	Problem	Language	Result	Execution time	Memory
1300568		KickingKun	Port Facility (JOI17_port_facility)	C++20	100 / 100	5087 ms	217180 KiB

port_facility

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define ull unsigned long long
#define ld long double
#define bigint __int128
#define emb emplace_back
#define pb push_back
#define pii pair <int, int>
#define fi first
#define se second
#define all(v) v.begin(), v.end()
#define Task "sample"

#define MASK(k) (1ull << k)
#define bitcnt(k) __builtin_popcount(k)
#define testBit(n, k) ((n >> k) & 1)
#define flipBit(n, k) (n ^ (1ll << k))
#define offBit(n, k) (n & ~MASK(k))
#define onBit(n, k) (n | (1ll << k))

template <class T> bool minimize(T &a, T b) {if (a > b) {a = b; return true;} return false;}
template <class T> bool maximize(T &a, T b) {if (a < b) {a = b; return true;} return false;}

const int N = 1e6 + 5, LG = 20, mod = 1e9 + 7;
const ll INF = 1e18;

int n;
pii range[N];

namespace sub2 {
	vector <int> adj[N];
	int color[N];

	bool dfs(int u, int c) {
		color[u] = c;
		for (int v: adj[u]) {
			if (color[v] == color[u]) return false;
			if (color[v] == 0) {
				bool check = dfs(v, 3 - c);
				if (!check) return false;
			}
		}
		return true;
	}

	void solve() {
		sort (range + 1, range + n + 1);
		for (int u = 1; u <= n; u++) {
			for (int v = u + 1; v <= n; v++) {
				if (range[v].fi < range[u].se && range[u].se < range[v].se) {
					adj[u].emplace_back(v);
					adj[v].emplace_back(u);
				}
			}
		}

		int ans = 1;
		for (int u = 1; u <= n; u++) if (!color[u]) {
			bool check = dfs(u, 1);
			if (!check) return (void)(cout << 0);
			ans = ans * 2 % mod;
		}
		cout << ans;
	}
}

namespace sub34 {
	struct SegmentTreeValue {
		vector <int> st;
		vector <bool> lazy;

		SegmentTreeValue (int n) {
			st.assign(n * 4 + 5, 0);
			lazy.assign(n * 4 + 5, false);
		}

		void push_down(int id) {
			if (lazy[id]) {
				st[id << 1] = st[id << 1 | 1] = st[id];
				lazy[id << 1] = lazy[id << 1 | 1] = true;
				lazy[id] = false;
			}
		}

		void update(int id, int l, int r, int u, int v, int val) {
			if (u > r || v < l) return;
			if (u <= l && r <= v) {
				st[id] = val;
				lazy[id] = true;
				return;
			}
			int mid = (l + r) >> 1; push_down(id);
			update(id << 1, l, mid, u, v, val);
			update(id << 1 | 1, mid + 1, r, u, v, val);
		}

		int get(int p) {
			int id = 1, l = 1, r = n;
			while (l < r) {
				int mid = (l + r) >> 1; push_down(id);
				if (p <= mid) id <<= 1, r = mid;
				else id = id << 1 | 1, l = mid + 1;
			}
			return st[id];
		}
	};

	int limit[N];

	vector <int> adj[N];
	int color[N];

	bool dfs(int u, int c) {
		color[u] = c;
		for (int v: adj[u]) {
			if (color[v] == color[u]) return false;
			if (color[v] == 0) {
				bool check = dfs(v, 3 - c);
				if (!check) return false;
			}
		}
		return true;
	}

	bool cmp(int u, int v) {
		return range[u].se > range[v].se;
	}

	void solve() {
		sort (range + 1, range + n + 1);

		for (int i = 1; i <= n; i++) {
			int low = i + 1, high = n, lim = -1;
			while (low <= high) {
				int mid = (low + high) >> 1;
				if (range[mid].fi < range[i].se)
					low = (lim = mid) + 1;
				else high = mid - 1;
			}
			limit[i] = lim;
		}

		vector <int> order(n); iota(all(order), 1);
		sort (all(order), cmp);

		SegmentTreeValue nxt(n), back(n), head(n);
		set <int> s;

		for (int i: order) {
			auto it = s.upper_bound(i);
			if (it != s.begin()) {
				int le = back.get(*prev(it));
				nxt.update(1, 1, n, le, *prev(it), i);
				head.update(1, 1, n, le, *prev(it), *prev(it));
			}
			if (it != s.end()) {
				int ri = nxt.get(*it);
				back.update(1, 1, n, *it, ri, *it);
			}

			nxt.update(1, 1, n, i, i, (it != s.end() ? *it : 1e9));
			back.update(1, 1, n, i, i, i);
			head.update(1, 1, n, i, i, i);
			s.emplace(i);

			if (limit[i] != -1) {
				// noi canh i->j (i < j <= limit[i] && B[i] < B[j])
				auto it = s.upper_bound(i);
				if (it != s.end()) {
					int p = *it, L = back.get(p), R = p;
					while (p <= limit[i]) {
						adj[i].emplace_back(p);
						adj[p].emplace_back(i);
						R = p; p = nxt.get(p);
					}
					R = head.get(R);
					nxt.update(1, 1, n, L, R, nxt.get(R));
					back.update(1, 1, n, L, R, L);
					head.update(1, 1, n, L, R, R);
				}
			}
		}

		// check exist answer

		int ans = 1;
		for (int u = 1; u <= n; u++) if (!color[u]) {
			bool check = dfs(u, 1);
			if (!check) return (void)(cout << 0);
			ans = ans * 2 % mod;
		}
		cout << ans;
	}
}

int main() {
	ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);

	if (fopen(Task".inp", "r")) {
		freopen(Task".inp", "r", stdin);
		freopen(Task".out", "w", stdout);
	}

	cin >> n;
	for (int i = 1; i <= n; i++)
		cin >> range[i].fi >> range[i].se;

	sub34::solve();
}

Compilation message (stderr)

port_facility.cpp: In function 'int main()':
port_facility.cpp:202:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  202 |                 freopen(Task".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
port_facility.cpp:203:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  203 |                 freopen(Task".out", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 56 / 56
• Subtask 4: 22 / 22