Submission #1300372

#TimeUsernameProblemLanguageResultExecution timeMemory
1300372KickingKunPort Facility (JOI17_port_facility)C++20
10 / 100
24 ms16692 KiB
#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 ""

#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;
	}

	ll 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 0;
			ans = ans * 2 % mod;
		}
		return ans;
	}
}

namespace sub34 {
	struct DSU {
		vector <int> lab;
		int components;

		DSU (int n) {
			lab.assign(n + 1, -1);
			components = n;
		}

		int find_set(int u) {
			return lab[u] < 0 ? u : lab[u] = find_set(lab[u]);
		}

		bool unite(int u, int v) {
			u = find_set(u); v = find_set(v);
			if (u == v) return false;
			if (lab[u] > lab[v]) swap(u, v);
			lab[u] += lab[v]; lab[v] = u;
			--components;
			return true;
		}
	};

	struct SegmentTree {
		vector <int> st;
		SegmentTree (int n) {
			st.assign(n * 4 + 5, 1e9);
		}

		void update(int id, int l, int r, int p, int val) {
			if (l == r) {
				st[id] = val;
				return;
			}
			int mid = (l + r) >> 1;
			if (p <= mid) update(id << 1, l, mid, p, val);
			else update(id << 1 | 1, mid + 1, r, p, val);
			st[id] = min(st[id << 1], st[id << 1 | 1]);
		}

		int get(int id, int l, int r, int u, int v) {
			if (u > r || v < l) return 1e9;
			if (u <= l && r <= v) return st[id];
			int mid = (l + r) >> 1;
			return min(get(id << 1, l, mid, u, v), get(id << 1 | 1, mid + 1, r, u, v));
		}
	};

	struct SuperSegmentTree {
		vector <int> st;
		vector <bool> lazy;

		SuperSegmentTree (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 nearAffect[N], limit[N];

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

	ll 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;
		}

		stack <int> st;
		for (int i = n; i > 0; i--) {
			while (!st.empty() && range[i].se > range[st.top()].se) st.pop();
			nearAffect[i] = (st.empty() ? -1 : st.top());
			if (nearAffect[i] > limit[i]) nearAffect[i] = -1;
			st.emplace(i);
		}

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

		DSU dsu(n);
		SegmentTree ST(n);

		set <int> s; 
		// SuperSegmentTree nxt(n), back(n);
		vector <int> nxt(n + 1, 1e9);

		for (int i: order) {
			auto it = s.upper_bound(i);
			if (it != s.begin()) nxt[*prev(it)] = i;
			if (it != s.end()) nxt[i] = *it;
			s.emplace(i);

			if (nearAffect[i] != -1) ST.update(1, 1, n, i, nearAffect[i]);
			if (limit[i] != -1) {
				int k = ST.get(1, 1, n, i + 1, limit[i]);
				if (k <= limit[i]) return 0;

				// 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;
					while (p <= limit[i]) {
						dsu.unite(i, p);
						p = nxt[p];
					}
					// nxt.update(1, 1, n, L, R, nxt.get(R));
					// back.update(1, 1, n, L, R, L);
				}
			}
		}

		int ans = 1;
		for (int i = 1; i <= dsu.components; i++)
			ans = ans * 2 % mod;
		return 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;

	ll ans1 = sub2::solve();
	ll ans2 = sub34::solve();
	if (ans1 == ans2) cout << ans1;
	else {
		assert (false);
	}
}

Compilation message (stderr)

port_facility.cpp: In function 'int main()':
port_facility.cpp:232:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  232 |                 freopen(Task".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
port_facility.cpp:233:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  233 |                 freopen(Task".out", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
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