Submission #110489

#	Time	Username	Problem	Language	Result	Execution time	Memory
110489		MetB	Teleporters (IOI08_teleporters)	C++14	100 / 100	704 ms	58472 KiB

teleporters

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

int n, m, mn, ans;

pair <int, int> a[3000000];
vector <int> v;

int nxt[3000001], c[3000000], u[3000000];
int level[3000000], to[3000001];

int main ()
{
	cin >> n >> m;
	
	for (int i = 0; i < n; i++)
	{
		scanf ("%d%d", &a[i].first, &a[i].second);
		nxt[a[i].first - 1] = 2 * i + 1;
		nxt[a[i].second - 1] = 2 * i + 2;

		if (a[mn].first > a[i].first) mn = i;
	}

	for (int i = 2000000; i >= 0; i--)
		if (!nxt[i]) nxt[i] = nxt[i + 1];

	to[0] = 2 * mn + 1;

	for (int i = 0; i < n; i++)
	{
		to[2 * i + 1] = nxt[a[i].second];
		to[2 * i + 2] = nxt[a[i].first];
	}

	int color = 1;

	for (int i = 0; i <= 2 * n; i++)
	{
		if (u[i]) continue;
		int x = i;
		u[x] = color;

		while (!u[to[x]])
		{
			level[to[x]] = level[x] + 1;
			u[to[x]] = color;
			x = to[x];
		}

		if (u[to[x]] == color)
		{
			if (color == 1) ans = level[x] - level[to[x]];
			else v.push_back (level[x] - level[to[x]] + 1);
		}
		color++;
	}

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

	for (int i = v.size () - 1; i >= 0 && m; i--)
	{
		ans += v[i] + 2;
		m--;
	}

	cout << ans + m / 2 * 4 + m % 2;
}

Compilation message (stderr)

teleporters.cpp: In function 'int main()':
teleporters.cpp:35:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf ("%d%d", &a[i].first, &a[i].second);
   ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 5 / 5
• Subtask 5: 5 / 5
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• Subtask 20: 5 / 5