Submission #782466

#	Time	Username	Problem	Language	Result	Execution time	Memory
782466		makanhulia	Naboj (COCI22_naboj)	C++17	0 / 110	48 ms	9568 KiB

naboj

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll MAXN = 2e5 + 5;
const ll MAXM = 5e5 + 5;

ll n, m;
vector<ll> adjl[MAXN], ans;
bool visited[MAXN], flag = false;

void dfs(ll now) {
  if (visited[now])
  {
    flag = true;
    return ;
  }
  visited[now] = true;

  vector<ll> adjn = adjl[now];
  for (int i = 0; i < adjn.size(); ++i)
  {
    ll nxt = adjn[i];
    if (visited[nxt]) {
      flag = true;
      return ;
    }
    dfs(nxt);

    if (flag) {
      return ;
    }
  }

  ans.push_back(now);
}

int main(){
  ios_base::sync_with_stdio(false); cin.tie(0);
  cin >> n >> m;
  for (int i = 0; i < m; ++i)
  {
    ll tmpa, tmpb;
    cin >> tmpa >> tmpb;
    adjl[tmpb].push_back(tmpa);
  }

  for (int i = 1; i <= n; ++i)
  {
    if (visited[i]) {
      continue ;
    }
    dfs(i);

    if (flag)
    {
      cout << "-1\n";
      return 0;
    }
  }

  if (flag)
  {
    cout << "-1\n";
    return 0;
  }

  cout << ans.size() << "\n";
  for (int i = ans.size()-1; i >= 0 ; --i)
  {
    cout << ans[i] << " 1\n";
  }
  return 0;
}

Compilation message (stderr)

naboj.cpp: In function 'void dfs(ll)':
naboj.cpp:20:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   20 |   for (int i = 0; i < adjn.size(); ++i)
      |                   ~~^~~~~~~~~~~~~

• Subtask 1: 0 / 15
• Subtask 2: 0 / 25
• Subtask 3: 0 / 70