938B - Run For Your Prize - CodeForces Solution

#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n;
	int a[100005];
	cin>>n;
	int k=0,lt=0,rt=0,l=1,r=1000000;
	for(int i=1;i<=n;i++)
	{
		cin>>a[i];
		if(a[i]>500000&&k==0)
		{
			k=i;
		}
	}
	if(k!=0)
	{
		for(int i=1;i<k;i++)
		{
			lt=lt+a[i]-l;
			l=a[i];
		}
		for(int i=n;i>=k;i--)
		{
			rt=rt+r-a[i];
			r=a[i];
		}
	}
	else
	{
		for(int i=1;i<=n;i++)
		{
			lt=lt+a[i]-l;
			l=a[i];
		}
	}
//	cout<<k<<" "<<lt<<" "<<rt<<endl;
	if(rt!=0&&lt!=0)
	cout<<max(rt,lt);
	else
	{
		if(rt==0)
		cout<<lt;
		else
		cout<<rt;
	}
	return 0;
}