Submission #898897

#	Time	Username	Problem	Language	Result	Execution time	Memory
898897		duckindog	Logičari (COCI21_logicari)	C++14	10 / 110	23 ms	7772 KiB

Main

// from duckindog wth depression
#include<bits/stdc++.h>

using namespace std;

const int N = 1e5 + 10;
int n;
vector<int> ad[N];
int low[N], num[N], it;
vector<int> circle;
bool dd[N];
void dfs(int u, int pre = 0) {
  num[u] = low[u] = ++it;
  int mku, mkv;
  for (int v : ad[u]) {
    if (v == pre) continue;
    if (num[v]) low[u] = min(low[u], num[v]);
    else {
      dfs(v, u);
      low[u] = min(low[u], low[v]);
    }
    if (low[v] != num[v]) {
      if (!dd[u]) circle.push_back(u);
      if (!dd[v]) circle.push_back(v);
      dd[u] = dd[v] = 1;
    }
  }

}

int32_t main() {
  cin.tie(0)->sync_with_stdio(0);

  if (fopen("duck.inp", "r")) {
    freopen("duck.inp", "r", stdin);
    freopen("duck.out", "w", stdout);
  }
  cin >> n;
  bool sub = 1;
  for (int i = 1; i <= n; ++i) {
    int u, v; cin >> u >> v;
    ad[u].push_back(v);
    ad[v].push_back(u);
    if (ad[u].size() > 2 || ad[v].size() > 2) sub = 0;
  }
  if (sub) {
    cout << (n % 4 == 0 ?  n / 2 : -1);
    return 0;
  }

  dfs(1, 0);
  for (int x : circle) cout << x << ' ';


}

Compilation message (stderr)

Main.cpp: In function 'void dfs(int, int)':
Main.cpp:14:7: warning: unused variable 'mku' [-Wunused-variable]
   14 |   int mku, mkv;
      |       ^~~
Main.cpp:14:12: warning: unused variable 'mkv' [-Wunused-variable]
   14 |   int mku, mkv;
      |            ^~~
Main.cpp: In function 'int32_t main()':
Main.cpp:35:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 |     freopen("duck.inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:36:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |     freopen("duck.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 40
• Subtask 4: 0 / 50