Submission #955651

#	Time	Username	Problem	Language	Result	Execution time	Memory
955651		thunopro	Bigger segments (IZhO19_segments)	C++14	100 / 100	67 ms	14932 KiB

segments

#include<bits/stdc++.h>
using namespace std ; 
#define maxn 500009 
#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(x) lower_bound(v.begin(),v.end(),x)-v.begin()+1 
#define TIME (1.0*clock()/TIME_PERS_SEC) 
#define re exit(0); 

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

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

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

mt19937 rng (time(0)) ; 

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 ; 
ll sum [maxn] ; 
int a [maxn] , pos [maxn] , dp [maxn] ; 
int main ()
{
	ios_base::sync_with_stdio(0); 
	cin.tie(0);cout.tie(0); 
//	rf () ; 
	cin >> n ; 
	for ( int i = 1 ; i <= n ; i ++ ) 
	{
		cin >> a [i] ; 
		sum [i] = sum [i-1] + a [i] ; 
	}
	for ( int i = 1 ; i <= n ; i ++ ) 
	{
		chkmax (pos[i],pos[i-1]) ; 
		dp [i] = dp [pos[i]] + 1 ; 
		int F = lower_bound(sum+1,sum+n+1,2*sum[i]-sum[pos[i]])-sum ; 
		if ( F <= n ) pos [F] = i ; 
	}
	cout << dp [n] ; 
}

Compilation message (stderr)

segments.cpp: In function 'void rf()':
segments.cpp:33:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |  freopen ("bai1.inp","r",stdin) ;
      |  ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 14 / 14
• Subtask 3: 10 / 10
• Subtask 4: 36 / 36
• Subtask 5: 27 / 27