oj.uz

답안 #941776

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
941776 2024-03-09T12:00:41 Z vjudge1 Chase (CEOI17_chase) C++17
40 / 100
 449 ms 524288 KB 
#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 = 1e14;
const int N = 1e5 + 5, K = 105;

int n, k;
int a[N];
vector<int> adj[N];

vector<int> sum;
vector<vector<vector<int>>> max1, max2;
vector<vector<int>> dp;

void dfs(int u, int p) {
  sum[u] = 0;
  for (int v : adj[u]) {
    if (v == p) continue;
    
    dfs(v, u);
    sum[u] += a[v];
  }
  
  for (int v : adj[u]) {
    if (v == p) continue;
    
    for (int i = 0; i <= k; ++i) {
      // nu folosesc
      if (dp[v][i] > max1[u][i][0]) {
        swap(max1[u][i][0], max2[u][i][0]);
        max1[u][i][0] = dp[v][i];
      } else max2[u][i][0] = max(max2[u][i][0], dp[v][i]);
      
      // folosesc
      if (i == 0) continue;
      if (dp[v][i - 1] > max1[u][i][1]) {
        swap(max1[u][i][1], max2[u][i][1]);
        max1[u][i][1] = dp[v][i - 1];
      } else max2[u][i][1] = max(max2[u][i][1], dp[v][i - 1]);
    }
  }
  
  for (int i = 0; i <= k; ++i) dp[u][i] = max({dp[u][i], max1[u][i][0], max1[u][i][1] + sum[u]});
}

int ans = 0;
void reroot(int u, int p) {
  auto dpu = dp[u], dpp = dp[p];
  auto sumu = sum[u], sump = sum[p];
  auto max1u = max1[u], max2u = max2[u];
  if (p != 0) {
    // pentru p
    sum[p] -= a[u];
    for (int i = 0; i <= k; ++i) {
      // nu folosesc
      dp[p][i] = 0;
      int maxi = max1[p][i][0];
      if (dp[u][i] == maxi) maxi = max2[p][i][0];
      dp[p][i] = max(dp[p][i], maxi);
      
      // folosesc
      if (i == 0) continue;
      maxi = max1[p][i][1];
      if (dp[u][i - 1] == maxi) maxi = max2[p][i][1];
      dp[p][i] = max(dp[p][i], maxi + sum[p]);
    }
    
    // pentru u
    sum[u] += a[p];
    for (int i = 0; i <= k; ++i) {
      // nu folosesc
      dp[u][i] = 0;
      if (dp[p][i] > max1[u][i][0]) {
        swap(max1[u][i][0], max2[u][i][0]);
        max1[u][i][0] = dp[p][i];
      } else max2[u][i][0] = max(max2[u][i][0], dp[p][i]);
      dp[u][i] = max(dp[u][i], max1[u][i][0]);
      
      // folosesc
      if (i == 0) continue;
      if (dp[p][i - 1] > max1[u][i][1]) {
        swap(max1[u][i][1], max2[u][i][1]);
        max1[u][i][1] = dp[p][i - 1];
      } else max2[u][i][1] = max(max2[u][i][1], dp[p][i - 1]);
      dp[u][i] = max(dp[u][i], max1[u][i][1] + sum[u]);
    }
  }
  
  ans = max(ans, dp[u][k]);
  
  for (int v : adj[u]) {
    if (v == p) continue;
    reroot(v, u);
  }
  
  dp[u] = dpu;
  dp[p] = dpp;
  max1[u] = max1u;
  max2[u] = max2u;
  sum[u] = sumu;
  sum[p] = sump;
}

int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  
  cin >> n >> k;
  
  for (int i = 1; i <= n; ++i) cin >> a[i];
  for (int i = 1; i < n; ++i) {
    int u, v;
    cin >> u >> v;
    adj[u].pb(v);
    adj[v].pb(u);
  }
  
  sum.assign(n + 1, 0);
  max1.assign(n + 1, vector<vector<int>>(k + 1, vector<int>(2, -INF)));
  max2.assign(n + 1, vector<vector<int>>(k + 1, vector<int>(2, -INF)));
  dp.assign(n + 1, vector<int>(k + 1));
  
  dfs(1, 0);
  //for (int i = 0; i <= k; ++i) cout << max1[4][i][0] << " " << max2[4][i][0] << " | " << max1[4][i][1] << " " << max2[4][i][1] << endl;
  
  reroot(1, 0);
  
  cout << ans;
}

/*
good:
0 0 | -10000000000000000 -10000000000000000
16 0 | 0 0
27 0 | 16 0

bad:
0 0 | -10000000000000000 -10000000000000000
16 0 | 0 0
24 0 | 16 0

*/

Subtask #1
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2652 KB Output is correct
2 Correct 1 ms 2652 KB Output is correct
3 Correct 1 ms 2652 KB Output is correct
4 Correct 1 ms 2652 KB Output is correct
5 Correct 1 ms 2652 KB Output is correct
6 Correct 1 ms 2652 KB Output is correct

Subtask #2
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2652 KB Output is correct
2 Correct 1 ms 2652 KB Output is correct
3 Correct 1 ms 2652 KB Output is correct
4 Correct 1 ms 2652 KB Output is correct
5 Correct 1 ms 2652 KB Output is correct
6 Correct 1 ms 2652 KB Output is correct
7 Correct 23 ms 21084 KB Output is correct
8 Correct 3 ms 4184 KB Output is correct
9 Correct 2 ms 3676 KB Output is correct
10 Correct 21 ms 14940 KB Output is correct
11 Correct 7 ms 6492 KB Output is correct
12 Correct 3 ms 3932 KB Output is correct

Subtask #3
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 449 ms 524288 KB Execution killed with signal 9
2 Halted 0 ms 0 KB -

Subtask #4
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2652 KB Output is correct
2 Correct 1 ms 2652 KB Output is correct
3 Correct 1 ms 2652 KB Output is correct
4 Correct 1 ms 2652 KB Output is correct
5 Correct 1 ms 2652 KB Output is correct
6 Correct 1 ms 2652 KB Output is correct
7 Correct 23 ms 21084 KB Output is correct
8 Correct 3 ms 4184 KB Output is correct
9 Correct 2 ms 3676 KB Output is correct
10 Correct 21 ms 14940 KB Output is correct
11 Correct 7 ms 6492 KB Output is correct
12 Correct 3 ms 3932 KB Output is correct
13 Runtime error 449 ms 524288 KB Execution killed with signal 9
14 Halted 0 ms 0 KB -