oj.uz

Submission #471764

# Submission time Handle Problem Language Result Execution time Memory
471764 2021-09-10T18:53:01 Z CaroLinda 3D Histogram (COCI20_histogram) C++14
20 / 110
 1022 ms 42364 KB 
#include <bits/stdc++.h>
 
#define sz(x) (int)(x.size())
#define debug 
#define ll long long
 
const int MAXN = 2e5+10 ;
 
using namespace std ;
 
struct Point
{
 
    ll x , y ;
 
    Point(ll x=0, ll y=0):x(x), y(y) {}
    
    Point operator - (Point other) const { return Point(x-other.x, y-other.y) ; } 
    ll operator % (Point other) const { return x*other.y - y*other.x ; }
    ll operator *(Point other) const { return x*other.x + y*other.y ; }
    void print() { printf("%lld %lld\n" , x , y) ; }
    void read() { scanf("%lld %lld", &x, &y) ; }
    int quadrant()
    {
        if(y >= 0 && x > 0) return 1 ;
        if( y > 0 && x <= 0 ) return 2 ;
        if( y <= 0 && x < 0 ) return 3 ;
        if( y < 0 && x <= 0 ) return 4 ;
        return 5 ; //origin
    }
} ;
 
int N ;
ll ans ; 
ll A[MAXN] , B[MAXN] , G[MAXN] , F[MAXN] ;
Point p[MAXN] ;
vector<Point> cht[MAXN*4] ;
int L[2] , R[2] , I[2] ;
int ptr[MAXN*4] ;
 
void build(int pos, int l, int r)
{
	cht[pos].clear() ;
	ptr[pos] = -1 ;
	
	if(r-l+1 <= 3 )
	{
		for(int i = l ; i <= r ; i++ ) cht[pos].push_back(p[i]) ;
		if(l == r ) return ;
		build(pos<<1 , l, (l+r)>>1 ) ;
		build(pos<<1|1 , (l+r+2)>>1 , r ) ;
		return ;
	}
	
	L[0] = r , R[0] = l-1 ;
	L[1] = l , R[1] = r+1 ;
	I[0] = -1 , I[1] = 1 ;
	
	for(int j = 0 , ant = 0; j < 2 ; j++, cht[pos].pop_back() , ant = sz(cht[pos]) )
		for(int i = L[j] ; i != R[j] ; i += I[j])
		{
			while( sz(cht[pos])-ant > 1  )
			{
				int q = sz(cht[pos]) ;
				if( (p[i]-cht[pos][q-2])%(cht[pos][q-1]-cht[pos][q-2]) > 0 ) break ;
				cht[pos].pop_back() ;
			}
			cht[pos].push_back(p[i]) ;
		}
	
	build(pos<<1 , l, (l+r)>>1 ) ;
	build(pos<<1|1 , (l+r+2)>>1 , r ) ;
	
}
 
void getAnswer(int pos, int l, int r, int beg, int en, Point px )
{
	if(l > en || r < beg ) return ;
	if( !(beg <= l && r <= en) )
	{
		getAnswer(pos<<1 , l, (l+r)>>1 , beg, en , px ) ;
		getAnswer( pos<<1|1 , (l+r+2)>>1 , r, beg, en , px ) ;
		return ;
	}
	if(cht[pos].empty()) return ;
	
	
	if( ptr[pos] == -1 || sz(cht[pos]) <= 3 || px.x == 0 || true )
	{
		ll cur = px*cht[pos][0] ;
		ptr[pos] = 0 ;
		for(int i = 1 ; i < sz(cht[pos]) ; i++ )
		{
			ll temp = px*cht[pos][i] ;
			if(temp <= cur) continue ;
			cur = temp ;
			ptr[pos] = i ;
		}
		ans = max(ans, cur) ;
		return ;
	}
	
	int tam = sz(cht[pos]) ;
	while( px*cht[pos][ (ptr[pos]-1+tam)%tam ] > px*cht[pos][ptr[pos]] )
	{
		ptr[pos]-- ;
		if(ptr[pos] == -1 ) ptr[pos] += tam ;
	}
	
	ans = max(ans, px*cht[pos][ptr[pos]] ) ;
	
}
 
void solve(int l, int r)
{
	if(l == r )
	{
		ans = max(ans, A[l]*B[l]) ;
		return ;
	}
	
	int mid = (l+r+1)>>1 ;
	
	F[mid-1] = A[mid-1] ;
	G[mid-1] = B[mid-1] ;
	for(int i = mid-2 ; i >= l ; i-- )
	{
		F[i] = min(F[i+1] , A[i] ) ;
		G[i] = min(G[i+1] , B[i] ) ;
	}
	
	F[mid] = A[mid] ;
	G[mid] = B[mid] ;
	for(int i = mid+1 ; i <= r ; i++ ) 
	{
		F[i] = min( F[i-1] , A[i] ) ;
		G[i] = min(G[i-1],B[i]) ;
	}
	for(int i = mid ; i <= r ; i++ ) p[i] = Point( G[i] , G[i]*(ll)i ) ;
	
	build(1,mid, r) ; 
	
	//Convex hull part
	int ptrF = mid , ptrG = mid ;
	for(int i = mid-1 ; i >= l ; i-- )
	{		
		while( ptrF <= r && F[ptrF] >= F[i] ) ptrF++ ;
		while( ptrG <= r && G[ptrG] > G[i] ) ptrG++ ;
		
		getAnswer( 1 , mid , r , ptrG, ptrF-1 , Point(F[i]*(1-i) , F[i] ) ) ;
		
		while( ptrG <= r && G[ptrG] >= G[i] ) ptrG++ ;
		ans = max(ans, F[i]*G[i]*( min(ptrF, ptrG) - i ) ) ;		
	}
	
	solve(l,mid-1) ;
	solve(mid, r) ;
}
 
int main()
{
	scanf("%d", &N ) ;
	for(int i = 1 ; i <= N ; i++ ) scanf("%lld %lld", &A[i], &B[i] ) ;
	
	solve(1,N) ;
	reverse(A+1, A+1+N) ;
	reverse(B+1, B+1+N ) ;
	solve(1,N) ;
	
	printf("%lld\n" , ans ) ;
	
}

Compilation message

histogram.cpp: In function 'int main()':
histogram.cpp:162:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  162 |  scanf("%d", &N ) ;
      |  ~~~~~^~~~~~~~~~~
histogram.cpp:163:38: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  163 |  for(int i = 1 ; i <= N ; i++ ) scanf("%lld %lld", &A[i], &B[i] ) ;
      |                                 ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 22328 KB Output is correct
2 Correct 18 ms 22348 KB Output is correct
3 Correct 14 ms 22308 KB Output is correct
4 Correct 20 ms 22416 KB Output is correct
5 Correct 15 ms 22348 KB Output is correct
6 Correct 15 ms 22348 KB Output is correct
7 Correct 20 ms 22348 KB Output is correct
8 Correct 19 ms 22348 KB Output is correct
9 Correct 19 ms 22320 KB Output is correct
10 Correct 20 ms 22348 KB Output is correct
11 Correct 12 ms 22196 KB Output is correct
12 Correct 15 ms 22320 KB Output is correct

Subtask #2
0 / 90.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 22328 KB Output is correct
2 Correct 18 ms 22348 KB Output is correct
3 Correct 14 ms 22308 KB Output is correct
4 Correct 20 ms 22416 KB Output is correct
5 Correct 15 ms 22348 KB Output is correct
6 Correct 15 ms 22348 KB Output is correct
7 Correct 20 ms 22348 KB Output is correct
8 Correct 19 ms 22348 KB Output is correct
9 Correct 19 ms 22320 KB Output is correct
10 Correct 20 ms 22348 KB Output is correct
11 Correct 12 ms 22196 KB Output is correct
12 Correct 15 ms 22320 KB Output is correct
13 Correct 666 ms 39356 KB Output is correct
14 Correct 733 ms 42040 KB Output is correct
15 Correct 668 ms 39632 KB Output is correct
16 Correct 671 ms 39708 KB Output is correct
17 Correct 907 ms 42364 KB Output is correct
18 Correct 746 ms 41620 KB Output is correct
19 Correct 838 ms 41028 KB Output is correct
20 Correct 846 ms 41672 KB Output is correct
21 Correct 675 ms 39744 KB Output is correct
22 Correct 1022 ms 42216 KB Output is correct
23 Incorrect 69 ms 23888 KB Output isn't correct
24 Halted 0 ms 0 KB -