Submission #427229

#	Time	Username	Problem	Language	Result	Execution time	Memory
427229		pavement	Port Facility (JOI17_port_facility)	C++17	0 / 100	1 ms	332 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, L[1000005], R[1000005], link[1000005], sz[1000005], r[1000005];
bool vis[1000005], col[1000005], cl[1000005];
vector<ii> curr;
set<int> Aseg, Bseg;
const int MOD = 1e9 + 7;
 
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;
}
 
main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> N;
	for (int i = 1; i <= N; i++) {
		link[i] = i;
		sz[i] = 1;
		cin >> L[i] >> R[i];
		cl[R[i]] = 1;
		r[L[i]] = r[R[i]] = i;
	}
	for (int i = 1; i <= 2 * N; i++) {
		if (!cl[i]) {
			bool A = 0, B = 0;
			auto it = Aseg.lower_bound(L[r[i]]);
			if (it != Aseg.end() && *it < R[r[i]]) A = 1;
			it = Bseg.lower_bound(L[r[i]]);
			if (it != Bseg.end() && *it < R[r[i]]) B = 1;
			if (A && B) return cout << "0\n", 0;
			else if (A) Bseg.insert(R[r[i]]);
			else Aseg.insert(R[r[i]]);
		}
	}
	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;
	cout << ans << '\n';
}

Compilation message (stderr)

port_facility.cpp:53:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   53 | main() {
      | ^~~~

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