This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
vector<queue<int>> adj;
vector<unordered_set<int>> c;
vector<int> ep;
void euler(int index, int last)
{
	c[last].insert(index);
	while (!adj[index].empty())
	{
		int node = adj[index].front();
		adj[index].pop();
		if (!c[node].count(index))
			euler(node, index);
	}
	ep.push_back(index);
}
int main()
{
	int N, M; cin >> N >> M;
	adj.resize(N);
	c.resize(N);
	for (int i = 0; i < M; i++)
	{
		int a, b;
		cin >> a >> b;
		a--; b--;
		adj[a].push(b);
		adj[b].push(a);
	}
	euler(0, 0);
	reverse(ep.begin(), ep.end());
	int g = 0;
	vector<int> occourence(ep.size(), -1);
	vector<int> linkedList(ep.size(), -1);
	iota(linkedList.begin(), linkedList.end(), 1);
	for (int i = 0; i < ep.size(); i++)
	{
		int value = ep[i];
		if (occourence[value] != -1)
		{
			int j = linkedList[occourence[value]];
			linkedList[occourence[value]] = i + 1;
			for (; j <= i; j = linkedList[j])
			{
				cout << ep[j] + 1 << ' ';
				occourence[ep[j]] = -1;
			}
			cout << '\n';
		}
		occourence[value] = i;
	}
	int i = 0;
	
	return 0;
}
Compilation message (stderr)
postmen.cpp: In function 'int main()':
postmen.cpp:48:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |  for (int i = 0; i < ep.size(); i++)
      |                  ~~^~~~~~~~~~~
postmen.cpp:43:6: warning: unused variable 'g' [-Wunused-variable]
   43 |  int g = 0;
      |      ^
postmen.cpp:69:6: warning: unused variable 'i' [-Wunused-variable]
   69 |  int i = 0;
      |      ^| # | Verdict  | Execution time | Memory | Grader output | 
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