Submission #777994

#	Time	Username	Problem	Language	Result	Execution time	Memory
777994		jamezzz	Teleporters (IOI08_teleporters)	C++17	100 / 100	985 ms	65536 KiB

teleporters

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

#define sf scanf
#define pf printf
#define fi first
#define se second
#define pb push_back
#define INF 1023456789
#define sz(x) ((int)x.size())
#define all(x) x.begin(),x.end()
typedef pair<int,int> ii;

#define maxn 1000005

int n,m,s[maxn],e[maxn],par[maxn<<2],sz[maxn<<2];
vector<ii> v;

int fp(int i){
	return par[i]==i?i:par[i]=fp(par[i]);
}

void join(int x,int y){
	x=fp(x),y=fp(y);
	if(x==y)return;
	if(sz[x]<sz[y])swap(x,y);
	par[y]=x;
	sz[x]+=sz[y];
}

int main(){
	sf("%d%d",&n,&m);
	for(int i=0;i<2*(m+n);++i)par[i]=i,sz[i]=1;
	for(int i=0;i<n;++i){
		sf("%d%d",&s[i],&e[i]);
		v.pb({s[i],2*i});
		v.pb({e[i],2*i+1});
	}
	sort(all(v));
	int src=v[0].se;
	for(auto[x,i]:v){
		int y=(i%2)?s[i>>1]:e[i>>1];//other endpoint
		int pos=lower_bound(all(v),ii(y+1,-1))-v.begin();
		if(pos==sz(v))continue;
		int j=v[pos].se;
		join(i,j);
	}
	vector<int> s;
	for(int i=0;i<2*n;++i){
		if(fp(i)==i&&fp(i)!=fp(src)){
			s.pb(sz[i]);
		}
	}
	int ans=sz[fp(src)];
	sort(all(s));
	for(int i=0;i<m;++i){
		if(!s.empty()){
			ans+=2+s.back();
			s.pop_back();
		}
		else ans+=1,s.pb(1);
	}
	pf("%d\n",ans);
}

Compilation message (stderr)

teleporters.cpp: In function 'int main()':
teleporters.cpp:32:4: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |  sf("%d%d",&n,&m);
      |    ^
teleporters.cpp:35:5: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 |   sf("%d%d",&s[i],&e[i]);
      |     ^

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 5 / 5
• Subtask 5: 5 / 5
• Subtask 6: 5 / 5
• Subtask 7: 5 / 5
• Subtask 8: 5 / 5
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• Subtask 15: 5 / 5
• Subtask 16: 5 / 5
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• Subtask 18: 5 / 5
• Subtask 19: 5 / 5
• Subtask 20: 5 / 5