Submission #795967

#	Time	Username	Problem	Language	Result	Execution time	Memory
795967		NeroZein	Spring cleaning (CEOI20_cleaning)	C++17	9 / 100	45 ms	8296 KiB

cleaning

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

#ifdef Nero
#include "Deb.h"
#else
#define deb(...)
#endif

const int N = 100005;

int leaves;
bool leaf[N]; 
vector<int> g[N]; 

void dfs (int v, int p) {
  if (g[v].size() == 1) {
    leaves++;
    leaf[v] = true;
  }
  for (int u : g[v]) {
    if (u != p) {
      dfs(u, v);
    }
  }
}

int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int n, q;
  cin >> n >> q;
  for (int i = 1; i < n; ++i) {
    int u, v;
    cin >> u >> v;
    g[u].push_back(v);
    g[v].push_back(u); 
  }
  dfs(1, 1);
  while (q--) {
    int d;
    cin >> d;
    vector<int> nodes(d);
    for (int i = 0; i < d; ++i) {
      cin >> nodes[i];
    }
    int ans = leaves;
    int tleaves = leaves + d;
    sort(nodes.begin(), nodes.end()); 
    for (int i = 0; i < d; ++i) {
      int j = i;
      while (j + 1 < d && nodes[j + 1] == nodes[j]) {
        j++; 
      }
      if (leaf[nodes[i]]) {
        tleaves--; 
        ans--;
      }
      int ch = j - i + 1; 
      int match_together = ch - (2 - (ch % 2));
      ans += match_together;
      ans += (ch - match_together) * 2;
      i = j; 
    }
    if (tleaves % 2) {
      cout << -1 << '\n';
    } else {
      cout << ans << '\n'; 
    }
  }
  return 0;
}

• Subtask 1: 0 / 0
• Subtask 2: 9 / 9
• Subtask 3: 0 / 9
• Subtask 4: 0 / 16
• Subtask 5: 0 / 19
• Subtask 6: 0 / 17
• Subtask 7: 0 / 30