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답안 #319186

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
319186 2020-11-04T12:38:22 Z VodkaInTheJar Dynamite (POI11_dyn) C++14
0 / 100
 513 ms 36068 KB 
#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#define endl '\n'

using namespace std;

const int maxn = 3e5 + 3; 

int n, m; 
bool is[maxn];
vector <pair <int, int> > adj[maxn];
void read()
{
	cin >> n >> m;
	for (int i = 1; i <= n; i++)
	cin >> is[i];
	
	for (int i = 1; i <= n-1; i++)
	{
		int a, b;
		cin >> a >> b;
		
		adj[a].push_back({0, b});
		adj[b].push_back({0, a});
	}
}

int depth[maxn], max_depth[maxn];
void pre_dfs(int ver, int par)
{
	max_depth[ver] = -1;
	if (is[ver])
	max_depth[ver] = depth[ver];
	
	for (auto i: adj[ver])
	if (i.second != par)
	{
		depth[i.second] = depth[ver] + 1; 
		pre_dfs(i.second, ver);
		max_depth[ver] = max(max_depth[ver], max_depth[i.second]);
	}
}

int cnt; 
int dfs(int ver, int par, int cover, int x)
{
	if (max_depth[ver] - depth[ver] <= cover)
	return 0;
	
	if (max_depth[ver] - depth[ver] <= x)
	{
		cnt++;
		return x; 
	}
	
	int curr_cover = cover;
	for (auto i: adj[ver])
	if (i.second != par)
	curr_cover = max(curr_cover, dfs(i.second, ver, max(0, curr_cover - 1), x));
    
    if (curr_cover == 0 && is[ver])
    {
		cnt++;
		return x;
	}
	
	return curr_cover - 1;
}

bool can(int x)
{
	cnt = 0;
	dfs(1, -1, 0, x);
    
    return cnt <= m; 	
}

void solve()
{
	depth[1] = 1;
	pre_dfs(1, -1);
	
	for (int i = 1; i <= n; i++)
	{
		for (auto &j: adj[i])
		j.first = max_depth[j.second];
		
		sort (adj[i].begin(), adj[i].end());
		reverse(adj[i].begin(), adj[i].end());
	}
	
	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
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 5 ms 7404 KB Output is correct
2 Correct 5 ms 7404 KB Output is correct
3 Incorrect 5 ms 7404 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 7404 KB Output is correct
2 Incorrect 5 ms 7404 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #3
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 6 ms 7404 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 6 ms 7404 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 11 ms 7948 KB Output is correct
2 Correct 18 ms 8680 KB Output is correct
3 Correct 23 ms 9452 KB Output is correct
4 Incorrect 41 ms 10732 KB Output isn't correct

Subtask #6
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 33 ms 10732 KB Output is correct
2 Correct 54 ms 11564 KB Output is correct
3 Correct 69 ms 11876 KB Output is correct
4 Incorrect 167 ms 15008 KB Output isn't correct

Subtask #7
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 78 ms 13560 KB Output is correct
2 Correct 79 ms 13284 KB Output is correct
3 Correct 88 ms 12900 KB Output is correct
4 Incorrect 296 ms 18660 KB Output isn't correct

Subtask #8
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 212 ms 19680 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 513 ms 27236 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #10
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 510 ms 36068 KB Output isn't correct
2 Halted 0 ms 0 KB -