Submission #104461

#	Time	Username	Problem	Language	Result	Execution time	Memory
104461		luciocf	Chase (CEOI17_chase)	C++14	100 / 100	914 ms	327576 KiB

chase

#include <bits/stdc++.h>

using namespace std;

const int maxn = 1e5+10;
const int maxk = 110;

typedef long long ll;

int n, k;

int a[maxn];
ll ant[2][maxn][maxk], ant_child[maxk];

ll soma[maxn];
ll d[2][maxn][maxk], ans;

vector<int> grafo[maxn];

void dfs(int u, int p)
{
	for (auto v: grafo[u])
	{
		if (v == p) continue;

		dfs(v, u);

		for (int i = 1; i <= k; i++)
		{
			ll x = soma[v]-1ll*a[u];

			ll D = max(d[0][v][i], x+d[0][v][i-1]);

			if (D > d[0][u][i]) d[1][u][i] = d[0][u][i], d[0][u][i] = D;
			else if (D > d[1][u][i]) d[1][u][i] = D;
		}
	}
}

void rotate(int u, int p)
{
	for (int i = 1; i <= k; i++)
		ans = max({ans, d[0][u][i], soma[u]+d[0][u][i-1]});

	for (auto v: grafo[u])
	{
		if (v == p) continue;

		for (int i = 1; i <= k; i++)
			ant_child[i] = d[0][v][i];

		for (int i = 1; i <= k; i++)
		{
			ant[0][u][i] = d[0][u][i], ant[1][u][i] = d[1][u][i];

			ll x = soma[v]-1ll*a[u];

			ll D = max(d[0][v][i], x+ant_child[i-1]);

			if (d[0][u][i] == D) d[0][u][i] = d[1][u][i];

			x = soma[u]-1ll*a[v];

			D = max(d[0][u][i], x+d[0][u][i-1]);
				
			if (D > d[0][v][i]) d[1][v][i] = d[0][v][i], d[0][v][i] = D;
			else if (D > d[1][v][i]) d[1][v][i] = D;
		}

		rotate(v, u);

		for (int i = 1; i <= k; i++)
			d[0][u][i] = ant[0][u][i], d[1][u][i] = ant[1][u][i];
	}
}

int main(void)
{
	scanf("%d %d", &n, &k);

	for (int i = 1; i <= n; i++)
		scanf("%d", &a[i]);

	for (int i = 1; i < n; i++)
	{
		int u, v;
		scanf("%d %d", &u, &v);

		grafo[u].push_back(v); grafo[v].push_back(u);
	}

	for (int i = 1; i <= n; i++)
		for (auto v: grafo[i])
			soma[i] += 1ll*a[v];

	dfs(1, 0);
	rotate(1, 0);

	printf("%lld\n", ans);
}

Compilation message (stderr)

chase.cpp: In function 'int main()':
chase.cpp:79:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &k);
  ~~~~~^~~~~~~~~~~~~~~~~
chase.cpp:82:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &a[i]);
   ~~~~~^~~~~~~~~~~~~
chase.cpp:87:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &u, &v);
   ~~~~~^~~~~~~~~~~~~~~~~

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