Submission #445821

#	Time	Username	Problem	Language	Result	Execution time	Memory
445821		Jasiekstrz	3D Histogram (COCI20_histogram)	C++17	0 / 110	2 ms	432 KiB

histogram

#include<bits/stdc++.h>
#define fi first
#define se second
using namespace std;
const int N=2e5;
const int PP=27e4;
const int INF=1e9+7;
int a[N+10];
int b[N+10];
pair<int,int> ea[N+10];
pair<int,int> eb[N+10];
int pot;
pair<int,int> tree[2*PP+10];
pair<int,int> min_pair(pair<int,int> x,pair<int,int> y)
{
	return {min(x.fi,y.fi),min(x.se,y.se)};
}
pair<int,int> read(int l,int r)
{
	pair<int,int> ans={INF,INF};
	for(l+=pot-1,r+=pot-1;l<=r;l/=2,r/=2)
	{
		if(l%2==1)
			ans=min_pair(ans,tree[l++]);
		if(r%2==0)
			ans=min_pair(ans,tree[r--]);
	}
	return ans;
}
long long ans=0;
void f(int l,int r)
{
	auto tmp=read(l,r);
	ans=max(ans,((long long)r-l+1)*tmp.fi*tmp.se);
	return;
}
void solve(int t[],pair<int,int> e[],int n)
{
	t[0]=t[n+1]=0;
	vector<int> st={0};
	for(int i=1;i<=n+1;i++)
	{
		while(t[st.back()]>t[i])
		{
			e[st.back()].se=i;
			st.pop_back();
		}
		if(t[st.back()]<t[i])
			e[i].fi=st.back();
		else
			e[i].fi=e[st.back()].fi;
		st.push_back(i);
	}
	return;
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	int n;
	cin>>n;
	for(int i=1;i<=n;i++)
		cin>>a[i]>>b[i];
	solve(a,ea,n);
	solve(b,eb,n);
	for(pot=1;pot<n;pot*=2);
	for(int i=1;i<=n;i++)
		tree[pot+i-1]={a[i],b[i]};
	for(int i=pot-1;i>=1;i--)
		tree[i]=min_pair(tree[2*i],tree[2*i+1]);
	for(int i=1;i<=n;i++)
	{
		f(ea[i].fi+1,i-1);
		f(eb[i].fi+1,i-1);
		f(i+1,ea[i].se-1);
		f(i+1,eb[i].se-1);
	}
	cout<<ans<<"\n";
	return 0;
}

• Subtask 1: 0 / 20
• Subtask 2: 0 / 90