Distances

input/code.cpp: In function 'int main()':
input/code.cpp:49:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0; i<ans.size(); ++i){
                ~^~~~~~~~~~~

#define MOD 1000000007
#include <bits/stdc++.h>
#include <numeric>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
void dfill(vector<vector<int>> &adj,vector<pair<int,vector<int>>> &adjr,int root,int parent=-1){
	adjr[root].first=parent;
	for(auto &i:adj[root]){
		if(i==parent) continue;
		adjr[root].second.push_back(i);
		dfill(adj,adjr,i,root);
	}
}
void edfs(vector<pair<int,vector<int>>>&,vector<int>&,int);
void sdfs(vector<pair<int,vector<int>>> &adj,vector<int> &ans,int root){
	ans.push_back(root);
	for(auto &i:adj[root].second){
		edfs(adj,ans,i);
	}
}
void edfs(vector<pair<int,vector<int>>> &adj,vector<int> &ans,int root){
	for(auto &i:adj[root].second){
		sdfs(adj,ans,i);
	}
	ans.push_back(root);
}
int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);

	int T;
	cin>>T;
	for(int T_Case=1;T_Case<=T;++T_Case){
		int n;
		vector<int> ans;
		cin>>n;
		vector<vector<int>> adj(n);
		vector<pair<int,vector<int>>> adjr(n);
		for(int i=0; i<n-1; ++i){
			int u,v;
			cin>>u>>v;
			adj[--u].push_back(--v);
			adj[v].push_back(u);
		}
		dfill(adj,adjr,0);
		edfs(adjr,ans,0);
		for(int i=0; i<ans.size(); ++i){
			cout<<ans[i]+1<<' ';
		}
		cout<<'\n';
	}
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: ACCEPTED