Submission #120374

#	Time	Username	Problem	Language	Result	Execution time	Memory
120374		tinder	Port Facility (JOI17_port_facility)	C++14	22 / 100	6081 ms	41212 KiB

port_facility

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

using ii = pair<int, int>;
const int maxn = 1e6 + 6;

int n, s[maxn], t[maxn];
vector<int> g[maxn];
int lvl[maxn], vis[maxn];

bool check(int source) {
	queue<int> Q;
	vis[source] = 1;
	Q.push(source);
	while(Q.size()) {
		int u = Q.front();
		Q.pop();
		for(int v : g[u]) {
			if(vis[v]) {
				if(lvl[v] == lvl[u]) {
					return false;
				}
			} else {
				lvl[v] = lvl[u] + 1;
				vis[v] = 1;
				Q.push(v);
			}
		}
	} return true;
}

int main(int argc, char const *argv[])
{
	scanf("%d", &n);
	vector<ii> tmp;
	for(int i = 1; i <= n; i++) {
		int _s, _t;
		scanf("%d %d", &_s, &_t);
		tmp.emplace_back(_s, _t);
	}
	// sort(tmp.begin(), tmp.end());
	for(int i = 0; i < n; i++) {
		s[i + 1] = tmp[i].first;
		t[i + 1] = tmp[i].second;
	}
	for(int i = 1; i <= n; i++) {
		for(int j = 1; j <= n; j++) {
			if(s[i] < s[j] and s[j] < t[i] and t[i] < t[j]) {
				g[i].emplace_back(j);
				g[j].emplace_back(i);
			}
		}
	}
	const int mod = 1e9 + 7;
	int ans = 1;
	for(int i = 1; i <= n; i++) {
		if(!vis[i]) {
			if(!check(i)) {
				puts("0");
				return 0;
			} else {
				ans <<= 1;
				if(ans >= mod) {
					ans -= mod;
				}
			}
		}
	}
	printf("%d\n", ans);
	return 0;
}

Compilation message (stderr)

port_facility.cpp: In function 'int main(int, const char**)':
port_facility.cpp:34:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
  ~~~~~^~~~~~~~~~
port_facility.cpp:38:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &_s, &_t);
   ~~~~~^~~~~~~~~~~~~~~~~~~

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