Submission #1797345

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Source Code Expand

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

using ll = long long;

template <typename T> T inf;
template <> constexpr int inf<int> = 1e9;
template <> constexpr ll inf<ll> = 1e18;

void dfs(int v, vector<vector<int>> const& g, vector<bool>& used, vector<int>& path) {
    if(!used[v]) {
        path.push_back(v + 1);
    }
    used[v] = true;
    for(auto to : g[v]) {
        if(used[to]) {
            continue;
        }
        dfs(to, g, used, path);
    }
}

int main() {
    int N, M;
    cin >> N >> M;
    vector<vector<int>> g(N);
    for(int i = 0; i < N; ++i) {
        int a, b;
        cin >> a >> b;
        g[a - 1].push_back(b - 1);
        g[b - 1].push_back(a - 1);
    }
    vector<int> path;
    vector<bool> used(N);
    dfs(0, g, used, path);
    reverse(path.begin(), path.end());
    dfs(0, g, used, path);
    cout << path.size() << endl;
    for(int i = 0; i < path.size(); ++i) {
        cout << path[i] << " \n"[i + 1 == path.size()];
    }
}

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