Distances

input/code.cpp: In function 'int main()':
input/code.cpp:45:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 1; i < ord.size(); ++i) {
                         ~~^~~~~~~~~~~~
input/code.cpp:47:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for (int j = 0; j <= ans.size(); ++j) {
                             ~~^~~~~~~~~~~~~
input/code.cpp:50:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 if (j < ans.size() && d[u][ans[j]] > 3) ok = false;
                     ~~^~~~~~~~~~~~

#include <bits/stdc++.h>

using namespace std;

int n;
vector<int> g[105];
int d[105][105];

int main(void) {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int ntest;
    cin >> ntest;
    while (ntest--) {
        cin >> n;
        for (int i = 1; i <= n; ++i) g[i].clear();
        for (int i = 1; i < n; ++i) {
            int u, v;
            cin >> u >> v;
            g[u].push_back(v);
            g[v].push_back(u);
        }

        memset(d, -1, sizeof d);
        for (int i = 1; i <= n; ++i) {
            queue<int> q;
            q.push(i);
            d[i][i] = 0;
            while (!q.empty()) {
                int u = q.front(); q.pop();
                for (auto v: g[u]) if (d[i][v] == -1) {
                    d[i][v] = d[i][u] + 1;
                    q.push(v);
                }
            }
        }

        vector<int> ord(n, 0);
        iota(ord.begin(), ord.end(), 1);
        sort(ord.begin(), ord.end(), [](int x, int y) {
                return d[1][x] < d[1][y];
             });
        vector<int> ans;
        ans.push_back(ord[0]);
        for (int i = 1; i < ord.size(); ++i) {
            int u = ord[i];
            for (int j = 0; j <= ans.size(); ++j) {
                bool ok = true;
                if (j && d[u][ans[j - 1]] > 3) ok = false;
                if (j < ans.size() && d[u][ans[j]] > 3) ok = false;
                if (ok) {
                    ans.insert(ans.begin() + j, u);
                    break;
                }
            }
        }

        for (auto x: ans) cout << x << ' ';
        cout << endl;
    }
    return 0;
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: WRONG ANSWER