Distances

#include <bits/stdc++.h>
using namespace std;
//#define int long long
vector<vector<int>> g;
vector<int> ans;

void dfs(int u, int p, int put){
    if(put) ans.push_back(u);
    for(int v : g[u]){
        if(v==p) continue;
        dfs(v, u, 1-put);
    }
    if(!put) ans.push_back(u);
}

signed main(){
    ios_base::sync_with_stdio(false); cin.tie(nullptr);
    g.resize(101);
    int t; cin >> t;
    while(t--){
        int n, xx, yy; cin >> n;
        for(int i=1; i<=n; ++i){
            g[i].clear();
        }
        for(int i=1; i<n; ++i){
            cin >> xx >> yy;
            g[xx].push_back(yy);
            g[yy].push_back(xx);
        }
        dfs(1, 0, 1);
        ans.clear();
        for(int i=0; i<n; ++i){
            cout << ans[i] << " ";
        }
        cout << "\n";
    }

}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: ACCEPTED