Submission #992694

#	Time	Username	Problem	Language	Result	Execution time	Memory
992694		cpptowin	Parkovi (COCI22_parkovi)	C++17	110 / 110	358 ms	56524 KiB

Main

#include <bits/stdc++.h>
#define fo(i, d, c) for (int i = d; i <= c; i++)
#define fod(i, c, d) for (int i = c; i >= d; i--)
#define maxn 1000010
#define N 1010
#define fi first
#define se second
#define pb emplace_back
#define en cout << "\n";
#define int long long
#define inf (int)1e18
#define pii pair<int, int>
#define vii vector<pii>
#define lb(x) x & -x
#define bit(i, j) ((i >> j) & 1)
#define offbit(i, j) (i ^ (1LL << j))
#define onbit(i, j) (i | (1LL << j))
#define vi vector<int>
template <typename T1, typename T2>
bool minimize(T1 &a, T2 b)
{
	if (a > b)
	{
		a = b;
		return true;
	}
	return false;
}
template <typename T1, typename T2>
bool maximize(T1 &a, T2 b)
{
	if (a < b)
	{
		a = b;
		return true;
	}
	return false;
}
using namespace std;
const int nsqrt = 450;
const int mod = 1e9 + 7;
int n, k;
vii ke[maxn];
bool covered[maxn], used[maxn];
int cnt, mid;
int dfs(int u, int par)
{
	if (ke[u].size() == 1 and u > 1)
		return 0;
	int dist = inf, reach = -inf;
	// dist : distance to nearest park
	// reach : how far inward can we place a park
	for (auto [v, w] : ke[u])
		if (v != par)
		{
			int a = dfs(v, u);
			if (a == 0 and covered[v])
			{
				maximize(reach, 0LL);
				minimize(dist, 0LL);
				continue;
			}
			if (a < 0 and a + w <= 0)
				covered[u] = 1;
			if (a < 0 and a + w > 0)
				a = 0;
			else
				a += w;
			if (a > mid)
			{
				a = min(-mid + w, 0LL);
				if (-mid + w <= 0)
					covered[u] = 1;
				covered[v] = 1;
				used[v] = 1;
				++cnt;
			}
			minimize(dist, a);
			maximize(reach, a);
		}
	if (-dist >= reach)
		return dist;
	return reach;
}
main()
{
#define name "TASK"
	if (fopen(name ".inp", "r"))
	{
		freopen(name ".inp", "r", stdin);
		freopen(name ".out", "w", stdout);
	}
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cin >> n >> k;
	int LIM = 0;
	fo(i, 1, n - 1)
	{
		int u, v, w;
		cin >> u >> v >> w;
		ke[u].pb(v, w);
		ke[v].pb(u, w);
		LIM += w;
	}
	int l = 0, r = LIM, ans = LIM;
	while (l <= r)
	{
		fo(i, 1, n) covered[i] = used[i] = 0;
		cnt = 0;
		mid = l + r >> 1;
		if (dfs(1, 1) > 0)
			used[1] = 1, ++cnt;
		else if (!covered[1])
			used[1] = 1, ++cnt;
		if (cnt <= k)
			r = mid - 1, ans = mid;
		else
			l = mid + 1;
	}
	cout << ans;
	en;
	mid = ans;
	fo(i, 1, n) covered[i] = used[i] = 0;
	cnt = 0;
	if (dfs(1, 1) > 0)
		used[1] = 1, ++cnt;
	else if (!covered[1])
		used[1] = 1, ++cnt;
	vi res;
	fo(i, 1, n) if (used[i]) res.pb(i);
	fo(i, 1, n) if ((int)res.size() < k and !used[i]) res.pb(i);
	for (int it : res)
		cout << it << ' ';
	en;
}

Compilation message (stderr)

Main.cpp:85:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   85 | main()
      | ^~~~
Main.cpp: In function 'int main()':
Main.cpp:110:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  110 |   mid = l + r >> 1;
      |         ~~^~~
Main.cpp:90:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |   freopen(name ".inp", "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:91:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   91 |   freopen(name ".out", "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 30 / 30
• Subtask 4: 60 / 60