Submission #481038

#	Time	Username	Problem	Language	Result	Execution time	Memory
481038		Kalashnikov	Port Facility (JOI17_port_facility)	C++17	22 / 100	6090 ms	8164 KiB

port_facility

#include <bits/stdc++.h>
 
#define ios ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define file(s) if (fopen(s".in", "r")) freopen(s".in", "r", stdin), freopen(s".out", "w", stdout)
#define all(a) a.begin() , a.end()
#define F first
#define S second
 
using namespace std;
using ll = long long;
 
const int N = 1e6+5 , inf = 2e9 + 7;
const ll INF = 1e18 ,   mod = 1e9+7 , P = 6547;

int u[N];
int p[N] , sz[N] , col[N] , q[N];
 
int get(int v) {
	if(v == p[v]) return v;
	return get(p[v]);
}

int getc(int v) {
	if(v == p[v]) return q[v];
	return getc(p[v])^1^q[v];
}
 
int merge(int a , int b) {
	int tb = b , ta = a;
	a = get(a);
	b = get(b);
	if(a == b) return 0;
	if(sz[a] < sz[b]) swap(a , b);
	if(getc(tb)%2 != getc(ta)%2) {
		q[b] ^= 1;
	}
	sz[a] += sz[b];
	p[b] = a;
	// cout << ta << ' ' << tb << '\n';
	return 1;
}

void solve(int tc) {
	int n;
	cin >> n;
	vector<pair<int,int>> v;
	for(int i = 1; i <= n; i ++) {
		int a , b;
		cin >> a >> b;
		v.push_back({a , b});
		p[i] = i;
		sz[i] = 1;
		col[i] = 1;
	}
	sort(all(v));

	set<pair<int,int>> st;
	int cnt = n;
	for(int i = 0; i < v.size(); i ++) {
		pair<int,int> to = v[i];
		int last = 2*n;
		while(st.size() && st.begin()->F < v[i].F) {
			st.erase(*st.begin());
		}
		auto it = st.begin();
		// cout << i << '\n';
		while(it != st.end() && it->F < to.S) {
			if(v[it->S - 1].F >= last) {
				cout << 0;
				return;
			}
			if(merge(it->S , i+1))
				cnt --;
			else {
				// cout << it->S << ' ' << i+1 << '\n';
				// cout << getc(it->S) << ' ' << getc(i+1) << '\n';
				if((getc(it->S) + getc(i+1)) % 2 == 0) {
					cout << 0;
					return;
				}
			}
			// if(i == 3) {
				// for(int j = 1; j <= n; j ++) {
						// cout << getc(j) << ' ';
				// }cout << '\n';
			// }
			last = v[it->S - 1].F;
			it ++;
		}
		st.insert({to.S , i+1});
	}

	ll ans = 1;
	for(int i = 1; i <= cnt; i ++) {
		ans *= 2;
		ans %= mod;
	}
	cout << ans;
}
/*
5
1 9
2 4
3 7
5 10
6 8


4
1 4
2 7
3 6
5 8
*/
main() {
    ios;
    int tt = 1 , tc = 0;
    // cin >> tt;
    while(tt --) {
        solve(++tc);
    }
    return 0;
}

Compilation message (stderr)

port_facility.cpp: In function 'void solve(int)':
port_facility.cpp:59:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |  for(int i = 0; i < v.size(); i ++) {
      |                 ~~^~~~~~~~~~
port_facility.cpp: At global scope:
port_facility.cpp:115:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  115 | main() {
      | ^~~~

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