Submission #934857

#	Time	Username	Problem	Language	Result	Execution time	Memory
934857		thunopro	Meetings (JOI19_meetings)	C++14	100 / 100	533 ms	1256 KiB

meetings

#include<bits/stdc++.h>
using namespace std ; 
#define maxn 200009
#define ll long long 
#define pb push_back 
#define fi first 
#define se second 
#define left id<<1
#define right id<<1|1 
#define re exit(0); 
#define _lower(x) lower_bound(v.begin(),v.end(),x)-v.begin()+1
const int mod = 1e9+7 ;
const int INF = 1e9 ; 

typedef vector<int> vi ; 
typedef pair<int,int> pii ; 
typedef vector<pii> vii ; 

template < typename T > void chkmin ( T &a , T b ) { if ( a > b ) a = b ; } 
template < typename T > void chkmax ( T &a , T b ) { if ( a < b ) a = b ; } 

void add ( int &a , int b ) 
{
	a += b ; 
	if ( a >= mod ) a -= mod ; 
	if ( a < 0 ) a += mod ; 
}

void rf () 
{
	freopen ("bai1.inp","r",stdin) ;
}

int _pow ( int a , int n ) 
{
	if ( n == 0 ) return 1 ; 
	int res = _pow (a,n/2) ; 
	if ( n % 2 ) return 1ll*res*res%mod*a%mod ; 
	else return 1ll*res*res%mod ; 
}

int n ; 

int Query ( int i , int j , int k ) ; 
void Bridge ( int i , int j ) ; 
void Solve ( int N ) ; 
//void Answer ( int x , int y ) ; 


void Answer ( int x , int y ) 
{
	if ( x > y ) swap (x,y) ;
	Bridge (x,y) ; 
}

void Calc ( vi v ) 
{
	if ( v.size () == 1 ) return ; 
	random_shuffle (v.begin(),v.end()) ; 
	map <int,vi> m ; 
	m [v[0]] . pb (v[0]) , m [v[1]] . pb (v[1]) ; 
	vi path ; 
	for ( int i = 2 ; i < v.size () ; i ++ ) 
	{
		int x = Query (v[0],v[1],v[i]) ; 
		if ( !m.count(x) ) path . pb (x) ; 
		m [x] . pb (v[i]) ; 
	}
	sort (path.begin(),path.end(),[&](int x , int y )
	{
		return (Query (v[0],x,y) == x ) ; 
	});  
	int last = v[0] ; 
	for ( auto x : path ) Answer (last,x) , last = x ; 
	Answer (last,v[1]) ; 
	for ( auto it : m ) Calc (it.second) ;  
}

void Solve ( int N ) 
{
	n = N ; 
	vi all (n) ; 
	for ( int i = 0 ; i < n ; i ++ ) all [i] = i ; 
	Calc (all) ; 
}

Compilation message (stderr)

meetings.cpp: In function 'void Calc(vi)':
meetings.cpp:63:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   63 |  for ( int i = 2 ; i < v.size () ; i ++ )
      |                    ~~^~~~~~~~~~~
meetings.cpp: In function 'void rf()':
meetings.cpp:31:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   31 |  freopen ("bai1.inp","r",stdin) ;
      |  ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 10 / 10
• Subtask 3: 12 / 12
• Subtask 4: 71 / 71