Submission #895915

#	Time	Username	Problem	Language	Result	Execution time	Memory
895915		thunopro	Split the sequence (APIO14_sequence)	C++14	100 / 100	1227 ms	91600 KiB

sequence

#include<bits/stdc++.h>
using namespace std ; 
#define ll long long 
#define ld double 
#define maxn 200009 
#define fi first 
#define se second 
#define pb push_back 
#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 ; 
const int LOG = 18 ; 

typedef vector<int> vi ; 
typedef pair<int,int> pii ; 
typedef vector<ll> vl ; 
typedef vector<pii> vii ; 
 
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 ; 
int a [maxn] , sum [maxn] ;

ll dp [maxn] ; 
int trace [maxn][209] ; 

struct line {
	int a ; ll b ; 
	int id ; 
	line ( int _a , ll _b , int _id ) {
		a = _a , b = _b , id = _id ; 
	}
	ll eval ( int x ) {
		return 1ll*x*a+b ; 
	}
};

struct CHT {
	vector <line> T ; 
	bool badline ( line A , line B , line C ) 
	{
		return (ld)(C.b-A.b)/(A.a-C.a) <= (ld)(B.b-A.b)/(A.a-B.a) ; 
	}
	void ins ( line m ) 
	{
		while (T.size()>=2) 
		{
			if ( badline(T[T.size()-2],T.back(),m)) T.pop_back() ; 
			else break ; 
		}
		T.pb(m) ; 
	}
	pair<ll,ll> get ( int x ) 
	{
		int l = 0 , r =T.size()-2 ; 
		while ( l <= r ) 
		{
			int mid = (l+r)/2 ; 
			if ( T[mid].eval(x) <= T[mid+1].eval(x) ) l = mid + 1 ; 
			else r = mid - 1 ; 
		}
		return {T[l].eval(x),T[l].id} ; 
	}
	void clear () 
	{
		T . clear () ; 
	}
};
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] , sum [i] = sum [i-1] + a [i] ; 
	
	k ++ ; 
	memset ( dp , 0x3f , sizeof dp ) ; 
	
	CHT T ; 
	for ( int r = 1 ; r <= k ; r ++ ) 
	{
		T.clear() ; 
		T.ins({0,0,0}) ; 
		for ( int i = 1 ; i <= n ; i ++ ) 
		{
			int C = sum [n] - sum [i] ; 
			auto F = T.get (-C) ; 
			if ( dp[i] < 1e18 ) T.ins({sum[i],dp[i],i}) ; 
			dp [i] = F.fi + 1ll*C*sum[i] ; 
			trace [i][r] = F.se ; 
		}
	}
	
	cout << dp [n] << "\n" ; 
	
	vi res ; 
	int pos = n ;
	while ( k > 1 ) 
	{
		pos = trace [pos][k] ; 
		res . pb (pos) ; 
		k -- ; 
	}
	
	reverse(res.begin(),res.end()) ; 
	for ( auto x : res ) cout << x << " " ; 
	
}

// range , error , check speical , ... 
// find key , find key 
//'-std=c++11' stay hard 
// there is no tomorrow 

Compilation message (stderr)

sequence.cpp: In function 'void rf()':
sequence.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: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 21 / 21
• Subtask 6: 29 / 29