Submission #834807

#	Time	Username	Problem	Language	Result	Execution time	Memory
834807		caganyanmaz	Shortcut (IOI16_shortcut)	C++17	0 / 100	1 ms	308 KiB

shortcut

#include <bits/stdc++.h>
#define pb push_back
#define int int64_t
#include "shortcut.h"
//#define DEBUGGING

#ifdef DEBUGGING
#include "../debug.h"
#else
#define debug(x...) void(42)
#endif
using namespace std;
constexpr static int SPECIAL_CHECK = 21;

constexpr static int MXN = 1e6 + 5;
constexpr static int INF = 1e18;
int pf[MXN];
array<int, 3> jv[MXN];
array<int, 2> iv[MXN];
vector<int> d, l;
int c, n;

static inline int dist(int a, int b)
{
	return pf[max(a, b)] - pf[min(a, b)];
}

vector<int> order;

bool check(int k)
{
	int xl = -INF, xr = INF, yl = -INF, yr = INF;
	int j = n;
	for (int l = n-1; l >= 0; l--)
	{
		int i = iv[l][1];
		while (j > 0 && jv[j-1][0] > k + iv[l][0])
			j--;
		if (j == n)
			continue;
		xl = max(xl,  pf[i] + d[i] - k + jv[j][2] + c); 
		xr = min(xr,  pf[i] - d[i] + k - jv[j][1] - c);
		yl = max(yl, -pf[i] + d[i] - k + jv[j][2] + c);
		yr = min(yr,  pf[i] - d[i] + k - jv[j][1] - c);
	}
	/*
	for (int i = 0; i < n; i++)
	{
		for (int j = i+1; j < n; j++)
		{
			if (dist(i, j) + d[i] + d[j] > k)
			{
				xl = max(xl, pf[j] + pf[i] - k + c + d[i] + d[j]);
				xr = min(xr, pf[j] + pf[i] + k - c - d[i] - d[j]);
				yl = max(yl, pf[j] - pf[i] - k + c + d[i] + d[j]);
				yr = min(yr, pf[j] - pf[i] + k - c - d[i] - d[j]);
			}
		}
	}
	*/
	xr++, yr++;

	if (xr <= xl || yr <= yl)
		return false;
	int xs = n, xe = n, ys = 1, ye = 1;
	for (int i = 0; i < n; i++)
	{
		while (xs > 0 && pf[xs-1] + pf[i] >= xl) xs--;
		while (xe > 0 && pf[xe-1] + pf[i] >= xr) xe--;
		while (ys < n && pf[ys] - pf[i] < yl) ys++;
		while (ye < n && pf[ye] - pf[i] < yr) ye++;
		if (max(xs, ys) < min(xe, ye))
			return true;
	}

	return false;
}

long long find_shortcut(int32_t _n, vector<int32_t> _l, vector<int32_t> _d, int32_t _c)
{
	c = _c;
	n = _n;
	for (int i : _l)
		l.pb(i);
	for (int i : _d)
		d.pb(i);
	array<int, 3> v = {0, 0, 0};
	for (int i = 1; i <= n; i++)
		pf[i] = pf[i-1] + l[i-1];
	for (int j = 0; j < n; j++)
		jv[j] = {pf[j] + d[j], d[j] - pf[j], d[j] + pf[j]};
	sort(jv, jv + n);
	for (int j = n-2; j >= 0; j--)
	{
		jv[j][1] = max(jv[j][1], jv[j+1][1]);
		jv[j][2] = max(jv[j][2], jv[j+1][2]);
	}
	for (int i = 0; i < n; i++)
		iv[i] = {pf[i] - d[i], i};
	sort(iv, iv + n);
	for (int i = 0; i < n; i++)
		debug(iv[i]);
	for (int j = 0; j < n; j++)
		debug(jv[j]);
	int ll = 0, rr = INF;
	while (rr - ll > 1)
	{
		int m = ll+rr>>1;
		if (check(m))
			rr = m;
		else
			ll = m;
	}
	return rr;
}

Compilation message (stderr)

shortcut.cpp: In function 'long long int find_shortcut(int32_t, std::vector<int>, std::vector<int>, int32_t)':
shortcut.cpp:108:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  108 |   int m = ll+rr>>1;
      |           ~~^~~
shortcut.cpp:87:16: warning: unused variable 'v' [-Wunused-variable]
   87 |  array<int, 3> v = {0, 0, 0};
      |                ^

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