Submission #893632

#	Time	Username	Problem	Language	Result	Execution time	Memory
893632		thunopro	Event Hopping 2 (JOI21_event2)	C++14	8 / 100	64 ms	4060 KiB

event2

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

const int mod = 1e9+7 ; 
const int INF = 1e9 ; 
const int LOG = 18 ; 

typedef vector<int> vi ; 
typedef vector<ll> vl ; 
typedef pair<int,int> pii ; 
typedef vector<pii> vii ; 
typedef pair<ll,ll> pll ;  

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

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 rf () 
{
	freopen ("bai1.inp","r",stdin) ; 
//	freopen ("bai1.out","w",stdout) ; 
}

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 , k ; 
pii a [maxn] ; 

void mapping () 
{
	vi v ;
	for ( int i = 1 ; i <= n ; i ++ ) v . pb (a[i].fi) , v . pb (a[i].se) ;
	sort (v.begin(),v.end()) ; 
	v.resize(unique(v.begin(),v.end())-v.begin()) ; 
	for ( int i = 1 ; i <= n ; i ++ ) 
	{
		a [i].fi = _lower (v,a[i].fi) ; 
		a [i].se = _lower (v,a[i].se) ; 
	}
}

bool check_sub1 () 
{
	for ( int i = 1 ; i < n ; i ++ ) if ( a[i].fi > a[i+1].fi ) return false ; 
	return true ; 
}

int bit [maxn] ; 
int dp [maxn] ; 
void update ( int x , int y ) 
{
	while ( x ) chkmax (bit[x],y) , x -= (x&-x) ; 
}
int get ( int x ) 
{
	int res = 0 ; 
	while ( x < maxn ) chkmax (res,bit[x]) , x += (x&-x) ; 
	return res ; 
}
void sub1 () 
{
	for ( int i = n ; i >= 1 ; i -- ) 
	{
		dp [i] = get (a[i].se) + 1 ;
		update (a[i].fi,dp[i]) ; 
	}

	if ( *max_element(dp+1,dp+n+1) < k ) 
	{
		cout << - 1 ; re 
	}
	int cur = 0 ; 
	vi res ;  
	
	for ( int i = 1 ; i <= n ; i ++ ) 
	{
		if ( a[i].fi >= cur && dp [i] + (int)res.size () >= k )
		{
			cur = a[i].se ; 
			res . pb (i) ;  
		}
		if ( res.size () == k ) break ;
	}
	
	for ( auto x : res ) cout << x << "\n" ; 
}

void sub2 () 
{
	vi res ; 
	for ( int mask = 0 ; mask < (1<<n) ; mask ++ ) 
	{
		if ( __builtin_popcount (mask) != k ) continue ; 
		vii arr ; 
		vi order ; 
		for ( int i = 0 ; i < n ; i ++ ) 
		{
			if ( mask >> i & 1 ) arr . pb (a[i+1]) , order . pb (i+1) ; 
		}
		sort (arr.begin(),arr.end()) ; 
		int last = 0 ; 
		bool ok = true ; 
		for ( auto x : arr ) 
		{
			if ( x.fi < last ) ok = false ; 
			last = x.se ; 
		}
		if ( ok == true ) 
		{
			if ( res.empty()) 
			{
				res = order ; 
				continue ; 
			}
			for ( int i = 0 ; i < k ; i ++ ) 
			{
				if ( order [i] != res [i] ) 
				{
					if ( order [i] < res [i] ) 
					{
						ok = true ; 
					}
					else ok = false ; 
					break ; 
				}
			}
			if ( ok == true ) res = order ; 
		}
	}

	if ( res.empty() ) cout << -1 ; 
	else 
	{
		for ( auto x : res ) cout << x << "\n" ; 
	}
}

const int N = 3e3 ; 
const int maxN = N + 9 ; 

int T [maxN*4] , lazy [maxN*4] ; 

void down ( int id ) 
{
	int &t = lazy [id] ; 
	T [left] += t , T [right] += t ; 
	lazy [left] += t , lazy [right] += t ; 
	t = 0 ; 
}
void update ( int id , int l , int r , int u , int v , int w ) 
{
	if ( l > v || r < u ) return ; 
	if ( u <= l && r <= v ) 
	{
		T [id] += w ; 
		lazy [id] += w ; 
		return ; 
	}
	down (id) ; 
	int mid = (l+r)/2 ; 
	update (left,l,mid,u,v,w) ;
	update (right,mid+1,r,u,v,w) ;
	T [id] = max (T[left],T[right]) ; 
}
int get ( int id , int l , int r , int u , int v ) 
{
	if ( l > v || r < u ) return 0 ; 
	if ( u <= l && r <= v ) return T [id] ; 
	int mid = (l+r)/2 ; 
	down (id) ;
	return max (get(left,l,mid,u,v),get(right,mid+1,r,u,v)) ; 
}

bool check_conquer ( int i ) 
{
	return ( get(1,1,N,a[i].fi,a[i].se-1) ) ; 
}
void sub3 () 
{
	vi res ; 
	for ( int i = 1 ; i <= n ; i ++ ) 
	{
		if ( check_conquer(i) ) continue ; 
		update (1,1,N,a[i].fi,a[i].se-1,1) ; 
		
		vii arr ; 
		for ( int j = i+1 ; j <= n ; j ++ ) 
		{
			if ( !check_conquer (j) ) arr . pb (a[j]) ; 
		}
		sort (arr.begin(),arr.end()) ; 
		int last = 0 , num = 0 ; 
		for ( auto x : arr ) 
		{
			if ( x.fi >= last ) num ++ , last = x.se ; 
			else last = min (last,x.se) ; 
		}
		if ( num + 1 + res.size () >= k ) res . pb (i) ; 
		else update (1,1,N,a[i].fi,a[i].se-1,-1) ; 
		if ( res.size () == k ) break ; 
	}
	
	if ( res.size () < k ) cout << - 1 ; 
	else 
	{
		for ( auto x : res ) cout << x << "\n" ; 
	}
	
}
int main () 
{
	ios_base::sync_with_stdio(0) ; 
	cin.tie(0) ; cout.tie(0) ; 
//	rf () ; 
	cin >> n >> k ; 
	for ( int i = 1 ; i <= n ; i ++ ) cin >> a[i].fi >> a[i].se ; 
	mapping () ;

	if ( check_sub1 () ) sub1 () ; 
	else if ( n <= 20 ) sub2 () ; 
	else if ( n <= 3000 ) sub3 () ; 

}

Compilation message (stderr)

event2.cpp: In function 'void sub1()':
event2.cpp:103:20: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  103 |   if ( res.size () == k ) break ;
      |        ~~~~~~~~~~~~^~~~
event2.cpp: In function 'void sub3()':
event2.cpp:219:30: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  219 |   if ( num + 1 + res.size () >= k ) res . pb (i) ;
      |        ~~~~~~~~~~~~~~~~~~~~~~^~~~
event2.cpp:221:20: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  221 |   if ( res.size () == k ) break ;
      |        ~~~~~~~~~~~~^~~~
event2.cpp:224:19: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  224 |  if ( res.size () < k ) cout << - 1 ;
      |       ~~~~~~~~~~~~^~~
event2.cpp: In function 'void rf()':
event2.cpp:35:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 |  freopen ("bai1.inp","r",stdin) ;
      |  ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 1 / 1
• Subtask 3: 0 / 31
• Subtask 4: 0 / 61