Submission #920092

#	Time	Username	Problem	Language	Result	Execution time	Memory
920092		Faisal_Saqib	Global Warming (CEOI18_glo)	C++17	55 / 100	2086 ms	6168 KiB

glo

#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
using namespace std;
const int N=2e5+100;
int a[N],cpy[N],n,x;
long long dp[N];
int suf[N];
int LIS()
{
	int ans=0;
	for(int i=0;i<=n;i++)
		dp[i]=3e9;
	dp[0]=-3e9;
	for(int i=0;i<n;i++)
		dp[lower_bound(dp,dp+n+1,cpy[i])-dp]=cpy[i];
	for(int i=0;i<=n;i++)
		if(dp[i]!=3e9)
			ans=max(ans,i);
	return ans;
}
void find_suf()
{
	int ans=0;
	for(int i=0;i<=n;i++)
		dp[i]=3e9;
	dp[0]=-3e9;
	suf[n]=0;
	for(int i=n-1;i>=0;i--)
	{
		cpy[i]=-cpy[i];
		int xc=lower_bound(dp,dp+n+1,cpy[i])-dp;
		ans=max(ans,xc);
		dp[xc]=cpy[i];
		suf[i]=xc;
		cpy[i]=-cpy[i];
	}
}
void reset()
{
	for(int i=0;i<n;i++)
		cpy[i]=a[i];
}
int main()
{
	cin>>n>>x;
	for(int i=0;i<n;i++)
		cin>>a[i];
	reset();
	// cout<<"INIT "<<LIS()<<endl;
	if(x==0)
	{
		cout<<LIS()<<'\n';
	}
	else if(x==1e9)
	{
		// For a prefix find the LIS 
		// And for each suffix find the LIS
		find_suf();
		int ans=0;
		int final=suf[0];
		for(int i=0;i<=n;i++)
			dp[i]=3e9;
		dp[0]=-3e9;
		for(int i=0;i<n;i++)
		{
			int xc=lower_bound(dp,dp+n+1,cpy[i])-dp;
			ans=max(ans,xc);
			dp[xc]=cpy[i];
			final=max(final,ans+suf[i+1]);
		}
		cout<<final<<'\n';
	}
	else
	{
		int ans=0;
		for(int i=0;i<n;i++)
		{
			cpy[i]-=x;
			ans=max(ans,LIS());
		}
		cout<<ans<<'\n';
	}
	return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 13 / 13
• Subtask 4: 10 / 10
• Subtask 5: 0 / 20
• Subtask 6: 17 / 17
• Subtask 7: 0 / 25