Distances

#include <bits/stdc++.h>

using namespace std;

using ll = long long;
#define pb push_back

const int MAX_N = 100;
int sol[1 + MAX_N];
vector <int> gr[1 + MAX_N];
vector <int> even_stack, order;

void dfs_order (int node, int par, int depth) {
    if (depth & 1)
        order.pb (node);
    else
        even_stack.pb (node);
    for (int son : gr[node])
        if (son != par)
            dfs_order (son, node, depth + 1);
    if (even_stack.back () == node)
        even_stack.pop_back (), order.pb (node);
}

void solveTest () {
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++)
        gr[i].clear ();
    for (int i = 1; i < n; i++) {
        int x, y;
        cin >> x >> y;
        gr[x].pb (y);
        gr[y].pb (x);
    }
    order.clear ();
    dfs_order (1, 0, 0);
    for (int x : order)
        cout << x << " ";
    cout << "\n";
}

int main () {
    int t;
    cin >> t;
    while (t--)
        solveTest ();
    return 0;
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: ACCEPTED