Submission #138423

#	Time	Username	Problem	Language	Result	Execution time	Memory
138423		MetB	Shortcut (IOI16_shortcut)	C++14	71 / 100	2037 ms	6012 KiB

shortcut

#include <algorithm>
#include <iostream>
#include <string.h>
#include <cstdlib>
#include <vector>
#include <string>
#include <bitset>
#include <math.h>
#include <queue>
#include <stack>
#include <set>
#include <map>
 
typedef long long ll;
typedef long double ld;
 
const ll MOD = 1e9 + 7, INF = 1e18 + 1;
 
using namespace std;

ll x[1000000], to_diff[1000000], n, c;

vector <ll> d;

pair <ll, ll> diff[1000000], sum[1000000];

struct BIT
{
	ll t1[1000000], t2[1000000];

	void update (ll x, ll d)
	{
		for (; x <= n; x |= (x + 1))
		{
			t1[x] = max (t1[x], d);
			t2[x] = min (t2[x], d);
		}
	}

	pair <ll, ll> get (ll r)
	{
		ll mx = -INF, mn = INF;

		for (;r >= 0; r = (r & (r + 1)) - 1)
		{
			mx = max (mx, t1[r]);
			mn = min (mn, t2[r]);
		}

		return {mn, mx};
	}

	void clear ()
	{
		for (ll i = 0; i < n; i++)
		{
			t1[i] = -INF;
			t2[i] = INF;
		}
	}
} t_diff, t_sum;

bool check (ll k)
{
	t_diff.clear ();
	t_sum.clear ();

	vector <ll> v (n);

	ll j = 0;
	for (ll i = 0; i < n; i++)
	{
		while (j < n && diff[j].first < sum[i].first - k)
			j++;

		ll cur = sum[i].second;

		v[cur] = j;
	}

	ll min_y_plus_z = -INF, max_y_plus_z = INF;
	ll min_y_minus_z = -INF, max_y_minus_z = INF;

	for (ll i = 0; i < n; i++)
	{
		pair <ll, ll> diff_border = t_diff.get (v[i] - 1);
		pair <ll, ll> sum_border = t_sum.get (v[i] - 1);

		if (diff_border.first != INF)
		{
			min_y_plus_z = max (min_y_plus_z, sum_border.second + x[i] + d[i] - k + c);
			max_y_plus_z = min (max_y_plus_z, diff_border.first + (x[i] - d[i]) + k - c);
			min_y_minus_z = max (min_y_minus_z, x[i] + d[i] - diff_border.first - k + c);
			max_y_minus_z = min (max_y_minus_z, (x[i] - d[i]) - sum_border.second + k - c);
		}

		t_diff.update (to_diff[i], x[i] - d[i]);
		t_sum.update (to_diff[i], x[i] + d[i]);
	}

	if (min_y_plus_z > max_y_plus_z) return false;
	if (min_y_minus_z > max_y_minus_z) return false;

	for (ll i = 0; i < n; i++)
		for (ll j = 0; j < i; j++)
			if (min_y_plus_z <= x[i] + x[j] && x[i] + x[j] <= max_y_plus_z &&
				min_y_minus_z <= x[i] - x[j] && x[i] - x[j] <= max_y_minus_z)
				return true;

	return false;
}

ll find_shortcut (int n, vector <int> l, vector <int> d, int c)
{
	::n = n;
	::c = c;

	for (auto a : d)
		::d.push_back (a);

	for (ll i = 1; i < n; i++)
	{

		x[i] = x[i-1] + (ll) l[i-1];
	}

	for (ll i = 0; i < n; i++)
	{
		sum[i] = {x[i] + d[i], i};
		diff[i] = {x[i] - d[i], i};
	}

	sort (sum, sum + n);
	sort (diff, diff + n);

	for (ll i = 0; i < n; i++)
		to_diff[diff[i].second] = i;

	ll L = 0, R = INF;

	while (L < R)
	{
		ll mid = (L + R) / 2;
		if (check (mid)) R = mid;
		else L = mid + 1;
	}

	return L;
}

/*int main ()
{
	int n, c;

	cin >> n;

	vector <int> l (n - 1), d (n);

	for (int i = 0; i < n - 1; i++)
		scanf ("%d", &l[i]);

	for (int i = 0; i < n; i++)
		scanf ("%d", &d[i]);

	cin >> c;

	cout << find_shortcut (n, l, d, c);


	return 0;
}*/

• Subtask 1: 9 / 9
• Subtask 2: 14 / 14
• Subtask 3: 8 / 8
• Subtask 4: 7 / 7
• Subtask 5: 33 / 33
• Subtask 6: 0 / 22
• Subtask 7: 0 / 4
• Subtask 8: 0 / 3