제출 #319164

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
319164		VodkaInTheJar	무제 (POI11_dyn)	C++14	20 / 100	28 ms	3932 KiB

Main

#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#define endl '\n'

using namespace std;

const int maxn = 1003; 

int n, m; 
vector <int> v; 
vector <int> adj[maxn];
void read()
{
	cin >> n >> m;
	for (int i = 1; i <= n; i++)
	{
		bool is;
		cin >> is;
		
		if (is)
		v.push_back(i);
	}
	
	for (int i = 1; i <= n-1; i++)
	{
		int a, b;
		cin >> a >> b;
		
		adj[a].push_back(b);
		adj[b].push_back(a);
	}
}

int dist[maxn][maxn];
void dfs(int start, int ver, int par)
{
	for (auto i: adj[ver])
	if (i != par)
	{
		dist[start][i] = dist[start][ver] + 1;
		dfs(start, i, ver);
	}
}

int cnt[maxn];
void remove_vertex(int ver, int x)
{
	for (int i = 1; i <= n; i++)
	if (dist[ver][i] <= x)
	cnt[i]--;
}

bool used[maxn], is_covered[maxn];
bool can(int x)
{
	priority_queue <pair <int, int> > q;
	for (int i = 1; i <= n; i++)
	{
		cnt[i] = 0;
		for (auto j: v)
	    if (dist[j][i] <= x)
	    cnt[i]++;
	}
	
	for (int i = 1; i <= n; i++)
	used[i] = false;
	
	for (auto i: v)
	is_covered[i] = false;
	
	for (int i = 1; i <= m; i++)
	{
		int maxs = -1, idx = -1;
		for (int j = 1; j <= n; j++)
		if (!used[j])
		if (cnt[j] > maxs)
		maxs = cnt[j], idx = j;
		
		used[idx] = true;
		for (auto i: v)
		if (!is_covered[i] && dist[idx][i] <= x)
		{
			is_covered[i] = true;
			remove_vertex(i, x);
		}
	}
	
	for (auto i: v)
	if (!is_covered[i])
	return false;
	
	return true; 
}

void solve()
{
	for (int i = 1; i <= n; i++)
	{
		dist[i][i] = 0;
		dfs(i, i, -1);
	}
	
	int low = 0, high = n; 
	while (low < high)
	{
		int mid = (low + high) / 2;
		if (can(mid))
		high = mid;
		
		else 
		low = mid+1;
	}
	
	cout << low << endl;
}

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);

	read();
	solve();
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10