oj.uz

Submission #472538

# Submission time Handle Problem Language Result Execution time Memory
472538 2021-09-13T17:22:16 Z CaroLinda 3D Histogram (COCI20_histogram) C++14
20 / 110
 851 ms 42256 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  )
	{
		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 ] > px*cht[pos][ptr[pos]] )
	{
		ptr[pos]++ ;
		if(ptr[pos] == tam ) ptr[pos] = 0 ;
	}
	
	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 14 ms 22328 KB Output is correct
2 Correct 18 ms 22444 KB Output is correct
3 Correct 19 ms 22348 KB Output is correct
4 Correct 19 ms 22412 KB Output is correct
5 Correct 15 ms 22400 KB Output is correct
6 Correct 17 ms 22420 KB Output is correct
7 Correct 21 ms 22348 KB Output is correct
8 Correct 17 ms 22348 KB Output is correct
9 Correct 17 ms 22424 KB Output is correct
10 Correct 15 ms 22340 KB Output is correct
11 Correct 14 ms 22220 KB Output is correct
12 Correct 20 ms 22348 KB Output is correct

Subtask #2
0 / 90.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 22328 KB Output is correct
2 Correct 18 ms 22444 KB Output is correct
3 Correct 19 ms 22348 KB Output is correct
4 Correct 19 ms 22412 KB Output is correct
5 Correct 15 ms 22400 KB Output is correct
6 Correct 17 ms 22420 KB Output is correct
7 Correct 21 ms 22348 KB Output is correct
8 Correct 17 ms 22348 KB Output is correct
9 Correct 17 ms 22424 KB Output is correct
10 Correct 15 ms 22340 KB Output is correct
11 Correct 14 ms 22220 KB Output is correct
12 Correct 20 ms 22348 KB Output is correct
13 Correct 704 ms 39556 KB Output is correct
14 Correct 712 ms 41928 KB Output is correct
15 Correct 615 ms 39732 KB Output is correct
16 Correct 660 ms 39640 KB Output is correct
17 Correct 851 ms 42256 KB Output is correct
18 Correct 627 ms 41540 KB Output is correct
19 Correct 715 ms 41036 KB Output is correct
20 Correct 745 ms 41672 KB Output is correct
21 Correct 670 ms 39796 KB Output is correct
22 Correct 712 ms 42224 KB Output is correct
23 Incorrect 75 ms 23972 KB Output isn't correct
24 Halted 0 ms 0 KB -