제출 #941730

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
941730		vjudge1	Chase (CEOI17_chase)	C++17	70 / 100	227 ms	97572 KiB

chase

#include <bits/stdc++.h>
using namespace std;

using ll = long long;
#define int ll

#define endl '\n'
#define pb push_back
using pi = pair<int, int>;
template<class T> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }

/*
dp[i][j] - subarborele lui i daca mai am j de aruncat
*/

const int INF = 1e16;

int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  
  int n, k;
  cin >> n >> k;
  
  vector<int> a(n + 1);
  for (int i = 1; i <= n; ++i) cin >> a[i];
  
  vector<vector<int>> adj(n + 1);
  for (int i = 1; i < n; ++i) {
    int u, v;
    cin >> u >> v;
    adj[u].pb(v);
    adj[v].pb(u);
  }
  
  vector<vector<int>> dp(n + 1, vector<int>(k + 1));
  function<void(int, int)> dfs = [&](int u, int p) {
    int S = 0;
    for (int v : adj[u]) {
      if (v == p) continue;
      
      dfs(v, u);
      S += a[v];
    }
    
    for (int v : adj[u]) {
      if (v == p) continue;
      
      for (int i = 0; i <= k; ++i) {
        // colectez
        if (i > 0) dp[u][i] = max(dp[u][i], S + max(dp[v][i - 1], 0LL));
        
        // nu colectez
        dp[u][i] = max(dp[u][i], dp[v][i]);
      }
    }
  };
  
  int ans = 0;
  if (n <= 1000) {
    for (int r = 1; r <= n; ++r) {
      for (int i = 1; i <= n; ++i) {
        for (int j = 0; j <= k; ++j) dp[i][j] = -INF;
      }
      dfs(r, 0);
      ans = max(ans, dp[r][k]);
    }
  } else {
    dfs(1, 0);
    ans = dp[1][k];
  }
  
  cout << ans;
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 30 / 30
• Subtask 4: 0 / 30