Submission #483039

#	Time	Username	Problem	Language	Result	Execution time	Memory
483039		ntabc05101	Chase (CEOI17_chase)	C++14	100 / 100	379 ms	254804 KiB

chase

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
const int maxn = 1e5+10, maxk = 110;
 
int n, k;
ll dp[maxn][maxk], dp2[maxn][maxk], ant[maxn][maxk], ans, vis[maxn], vet[maxn];
 
vector <int> graph[maxn];
 
void dfs(int u, int f = 0)
{
	for(int v: graph[u])
	{	
		if(v == f) continue;
		dfs(v, u);
 
		for(int i = 1 ; i <= k ; ++i)
		{
			ll val = max(dp[v][i-1] + vis[v] - vet[u], dp[v][i]);
		
			if(val > dp[u][i]) dp2[u][i] = dp[u][i], dp[u][i] = val;
			else if(val > dp2[u][i]) dp2[u][i] = val;
		}
	}
}
 
void rotate(int u, int f = 0)
{
	for(int i = 1 ; i <= k ; ++i)
	{
		ans = max({ans, dp[u][i], dp[u][i-1] + vis[u]});
	}
 
	for(int v: graph[u])
	{
		if(v == f) continue;
 
		for(int i = 1 ; i <= k ; ++i)
		{
			ant[u][i] = dp[u][i];
			
			ll val = max(dp[v][i], dp[v][i-1] + vis[v] - vet[u]);
 
			if(val == dp[u][i])
			{
				dp[u][i] = dp2[u][i];
			}
		}
 
		for(int i = 1 ; i <= k ; ++i)
		{
			ll val = max(dp[u][i], dp[u][i-1] + vis[u] - vet[v]);
 
			if(val > dp[v][i]) dp2[v][i] = dp[v][i], dp[v][i] = val;
			else if(val > dp2[v][i]) dp2[v][i] = val;
		}
 
		rotate(v, u);
 
		for(int i = 1 ; i <= k ; ++i) dp[u][i] = ant[u][i];
	}
}
 
int main()
{
	cin >> n >> k;
 
	for(int i = 1 ; i <= n ; ++i) cin >> vet[i];
 
	for(int i = 1 ; i < n ; ++i)
	{
		int u, v;
		cin >> u >> v;
 
		graph[u].push_back(v);
		graph[v].push_back(u);
	}
 
	for(int i = 1 ; i <= n ; ++i)
	{
		for(int v: graph[i])
		{
			vis[i] += vet[v];
		}
	}
 
	dfs(1);
	rotate(1);
 
	cout << ans << '\n';
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 30 / 30
• Subtask 4: 30 / 30