Submission #427388

#	Time	Username	Problem	Language	Result	Execution time	Memory
427388		pavement	Port Facility (JOI17_port_facility)	C++17	78 / 100	3319 ms	1015544 KiB

port_facility

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#ifdef _WIN32
#define getchar_unlocked _getchar_nolock
#endif
//#define int long long
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define ppb pop_back
#define eb emplace_back
#define g0(a) get<0>(a)
#define g1(a) get<1>(a)
#define g2(a) get<2>(a)
#define g3(a) get<3>(a)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef double db;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef tree<ii, null_type, less<ii>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
 
int N, ans, lft[1000005], rig[1000005], L[1000005], R[1000005], link[1000005], sz[1000005], r[1000005];
bool inv, col[100005], vis[1000005], cl[1000005];
vector<ii> curr;
set<int> seg;
const int MOD = 1e9 + 7;

void read(int &v) {
	v = 0;
	char ch = getchar_unlocked();
	for (; ch < '0' || ch > '9'; ch = getchar_unlocked());
	for (; '0' <= ch && ch <= '9'; ch = getchar_unlocked())
		v = (v << 3) + (v << 1) + (ch & 15);
}
 
bool is(int a, int b) {
	if (L[a] > L[b]) return is(b, a);
	return R[b] > R[a] && R[a] > L[b];
}
 
int find(int x) {
	if (x == link[x]) return x;
	return link[x] = find(link[x]);
}
 
void unite(int a, int b) {
	a = find(a);
	b = find(b);
	if (a == b) return;
	if (sz[b] > sz[a]) swap(a, b);
	sz[a] += sz[b];
	link[b] = a;
}
 
void go(int n);
 
struct node {
	node *left, *right;
	int S, E;
	vector<ii> val;
	node(int _s, int _e) : S(_s), E(_e) {
		if (S == E) return;
		int M = (S + E) >> 1;
		left = new node(S, M);
		right = new node(M + 1, E);
	}
	void upd(int p, int v, int idx) {
		val.eb(v, idx);
		if (S == E) return;
		int M = (S + E) >> 1;
		if (p <= M) left->upd(p, v, idx);
		else right->upd(p, v, idx);
	}
	void getall(int l, int r, int curr) {
		if (l > E || r < S) return;
		if (l <= S && E <= r) {
			vector<int> tmp;
			while (!val.empty() && val.back().first > r) {
				tmp.pb(val.back().second);
				val.ppb();
			}
			for (int i : tmp) {
				if (!vis[i]) col[i] = col[curr] ^ 1, go(i);
				else if (col[i] == col[curr]) inv = 1;
			}
			return;
		}
		left->getall(l, r, curr);
		right->getall(l, r, curr);
	}
} *root;
 
struct node2 {
	node2 *left, *right;
	int S, E;
	vector<ii> val;
	node2(int _s, int _e) : S(_s), E(_e) {
		if (S == E) return;
		int M = (S + E) >> 1;
		left = new node2(S, M);
		right = new node2(M + 1, E);
	}
	void upd(int p, int v, int idx) {
		val.eb(v, idx);
		if (S == E) return;
		int M = (S + E) >> 1;
		if (p <= M) left->upd(p, v, idx);
		else right->upd(p, v, idx);
	}
	void getall(int l, int r, int curr) {
		if (l > E || r < S) return;
		if (l <= S && E <= r) {
			vector<int> tmp;
			while (!val.empty() && val.back().first < l) {
				tmp.pb(val.back().second);
				val.ppb();
			}
			for (int i : tmp) {
				if (!vis[i]) col[i] = col[curr] ^ 1, go(i);
				else if (col[i] == col[curr]) inv = 1;
			}
			return;
		}
		left->getall(l, r, curr);
		right->getall(l, r, curr);
	}
} *root2;
 
void go(int n) {
	vis[n] = 1;
	root->getall(L[n], R[n], n);
	root2->getall(L[n], R[n], n);
}
 
main() {
	read(N);
	root = new node(1, 2 * N);
	root2 = new node2(1, 2 * N);
	for (int i = 1; i <= N; i++) {
		link[i] = i;
		sz[i] = 1;
		read(L[i]);
		read(R[i]);
		cl[R[i]] = 1;
		r[L[i]] = r[R[i]] = i;
	}
	for (int i = 1; i <= 2 * N; i++)
		if (cl[i]) root->upd(L[r[i]], i, r[i]);
	for (int i = 2 * N; i >= 1; i--)
		if (!cl[i]) root2->upd(R[r[i]], i, r[i]);
	for (int i = 1; i <= N; i++)
		if (!vis[i]) go(i);
	if (inv) return puts("0"), 0;
	for (int i = 1; i <= 2 * N; i++) {
		if (cl[i]) {
			int pos = -1, cnt = 0;
			for (int j = (int)curr.size() - 1; j >= 0; j--) {
				if (find(r[i]) == find(curr[j].first)) {
					pos = j;
					break;
				} else unite(r[i], curr[j].first), cnt += curr[j].second;
			}
			if (pos == -1) while (1) {}
			for (int k = 0, run = curr.size() - pos; k < run - 1; k++) curr.ppb();
			curr.back().second += cnt - 1;
			if (curr.back().second == 0) curr.ppb();
		} else {
			curr.eb(r[i], 1);
		}
	}
	ans = 1;
	for (int i = 1; i <= N; i++)
		if (i == find(i)) ans *= 2, ans %= MOD;
	printf("%d\n", ans);
}

Compilation message (stderr)

port_facility.cpp:141:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  141 | main() {
      | ^~~~

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 56 / 56
• Subtask 4: 0 / 22