Submission #74224

#	Time	Username	Problem	Language	Result	Execution time	Memory
74224		TadijaSebez	Port Facility (JOI17_port_facility)	C++11	100 / 100	3085 ms	562856 KiB

port_facility

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define mp make_pair
#define pb push_back
const int N=2000050;
const int M=N*2;
const int mod=1e9+7;
int pos(int x){ return x<<1;}
int neg(int x){ return x<<1|1;}
struct DSU
{
	int p[M];
	void init(){ for(int i=0;i<N;i++) p[i]=i;}
	DSU(){ init();}
	int Find(int x){ return p[x]==x?x:p[x]=Find(p[x]);}
	void Union(int x, int y){ p[Find(x)]=Find(y);}
} Tree;
set<pair<int,int> > st;
int l[N],r[N],id[N];
bool comp(int i, int j){ return l[i]<l[j] || l[i]==l[j] && r[i]<r[j];}
int main()
{
	int n,i;
	scanf("%i",&n);
	for(i=1;i<=n;i++) scanf("%i %i",&l[i],&r[i]),id[i]=i;
	sort(id+1,id+1+n,comp);
	for(i=1;i<=n;i++)
	{
		int j=id[i];
		set<pair<int,int> >::iterator it;
		it=st.upper_bound(mp(r[j],j));
		int lst=0;
		if(it!=st.begin()){ it--;lst=it->second;}
		for(it=st.lower_bound(mp(l[j],j));it!=st.upper_bound(mp(r[j],j));it++)
		{
			Tree.Union(pos(it->second),neg(j));
			Tree.Union(neg(it->second),pos(j));
			if(Tree.Find(pos(j))==Tree.Find(neg(lst))) break;
		}
		st.insert(mp(r[j],j));
	}
	int sol=1;
	for(i=1;i<=n;i++)
	{
		if(Tree.Find(pos(i))==pos(i)) sol=sol*2%mod;
		if(Tree.Find(pos(i))==Tree.Find(neg(i))) sol=0;
	}
	printf("%i\n",sol);
	return 0;
}

Compilation message (stderr)

port_facility.cpp: In function 'bool comp(int, int)':
port_facility.cpp:21:57: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
 bool comp(int i, int j){ return l[i]<l[j] || l[i]==l[j] && r[i]<r[j];}
                                              ~~~~~~~~~~~^~~~~~~~~~~~
port_facility.cpp: In function 'int main()':
port_facility.cpp:25:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%i",&n);
  ~~~~~^~~~~~~~~
port_facility.cpp:26:46: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(i=1;i<=n;i++) scanf("%i %i",&l[i],&r[i]),id[i]=i;
                    ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~

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