Submission #133816

#	Time	Username	Problem	Language	Result	Execution time	Memory
133816		MetB	Roller Coaster Railroad (IOI16_railroad)	C++14	0 / 100	666 ms	42340 KiB

railroad

#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 p[1000000], sz[1000000];

set <ll> mp;

struct stop
{
	ll x;
	bool op, left;

	bool operator < (const stop& b)
	{
		if (x == b.x) return op > b.op;
		else return x < b.x;
	}
};

struct edge
{
	ll u, v, c;

	bool operator < (const edge& b)
	{
		return c < b.c;
	}
};

vector <stop> v;

ll find (ll x)
{
	if (p[x] == x) return x;
	else return p[x] = find (p[x]);
}

void unite (ll a, ll b)
{
	a = find (a);
	b = find (b);

	if (a == b) return;

	if (sz[a] < sz[b]) swap (a, b);

	p[b] = a;

	sz[a] += sz[b];
}

ll ind (ll a, vector <int>& s)
{
	return lower_bound (s.begin(), s.end(), a) - s.begin ();
}

ll plan_roller_coaster (vector <int> s, vector <int> t)
{
	ll ans = 0, balance = 0;

	vector <int> coord;

	for (ll i = 0; i < s.size (); i++)
	{
		if (s[i] > t[i])
		{
			v.push_back ({s[i], true, true});
			v.push_back ({t[i], false, true});
		}
		else
		{
			v.push_back ({s[i], true, false});
			v.push_back ({t[i], false, false});
		}

		mp.insert (s[i]);
		mp.insert (t[i]);
	}

	for (auto a : mp)
		coord.push_back (a);

	for (ll i = 0; i < coord.size (); i++)
	{
		sz[i] = 1;
		p[i] = i;
	}

	v.push_back ({1, true, true});
	v.push_back ({coord.back (), false, true});

	for (ll i = 0; i < s.size (); i++)
		unite (ind (s[i], coord), ind (t[i], coord));

	sort (v.begin(), v.end());

	vector <edge> tr;

	for (ll i = 0; i < v.size (); i++)
	{
		if (v[i].left ^ v[i].op) balance++;
		else balance--;

		vector <edge> tr;

		if (i != v.size () - 1) 
		{
			ans += max (0LL, balance * (v[i+1].x - v[i].x));
			if (balance) unite (ind (v[i].x, coord), ind (v[i+1].x, coord));
			else tr.push_back ({ind (v[i].x, coord), ind (v[i+1].x, coord), (v[i+1].x - v[i].x)});
		}
	}

	sort (tr.begin(), tr.end());

	for (edge e : tr)
	{
		if (find (e.u) != find (e.v))
		{
			ans += e.c;
			unite (e.u, e.v);
		}
	}

	return ans;
}

Compilation message (stderr)

railroad.cpp: In function 'll plan_roller_coaster(std::vector<int>, std::vector<int>)':
railroad.cpp:80:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (ll i = 0; i < s.size (); i++)
                 ~~^~~~~~~~~~~
railroad.cpp:100:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (ll i = 0; i < coord.size (); i++)
                 ~~^~~~~~~~~~~~~~~
railroad.cpp:109:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (ll i = 0; i < s.size (); i++)
                 ~~^~~~~~~~~~~
railroad.cpp:116:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (ll i = 0; i < v.size (); i++)
                 ~~^~~~~~~~~~~
railroad.cpp:123:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if (i != v.size () - 1) 
       ~~^~~~~~~~~~~~~~~~

• Subtask 1: 0 / 11
• Subtask 2: 0 / 23
• Subtask 3: 0 / 30
• Subtask 4: 0 / 36