Astralis session I

input/code.cpp: In function 'int main()':
input/code.cpp:48:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |     for (int i = 0; i < e.size(); ++i){
      |                     ~~^~~~~~~~~~

using namespace std;

#include <iostream>
#include <algorithm>
#include <vector>
#include <utility>
#include <unordered_set>  


int dfs(vector< unordered_set<int> >&e, int k, int parent){
    int sum = 1;
    for (auto i = begin(e[k]); i != end(e[k]); ++i) {
        if (*i != parent)
            sum += dfs(e, (*i), k);
    }
    return sum;
}

void dfs_print(vector< unordered_set<int> >&e, int k, int parent, char letter){
    cout << letter;
    for (auto i = begin(e[k]); i != end(e[k]); ++i) {
        if (*i != parent)
            dfs_print(e, (*i), k, letter);
    }
}


int main(){

    int n;

    cin >> n;

    vector< unordered_set<int> > adj = vector<unordered_set<int> >(n+1);
    vector< pair<int, int> > e;
    for (int i = 0; i < n-1; ++i)
    {
        int aux1, aux2;

        cin >> aux1 >> aux2;

        adj[aux1].insert(aux2);
        adj[aux2].insert(aux1);
        
        e.push_back(make_pair(aux1, aux2));
    }

    for (int i = 0; i < e.size(); ++i){
        int v1 = e[i].first;
        int v2 = e[i].second;
        
        adj[v1].erase(v2);
        adj[v2].erase(v1);

        if (dfs(adj, v1, -1) == dfs(adj, v2, -1))
        {
            cout << "YES" << endl;
            dfs_print(adj, v1, -1, 'U');
            dfs_print(adj, v2, -1, 'M');
            cout << endl;
            return 0;
        }

        adj[v1].insert(v2);
        adj[v2].insert(v1);
    }

    cout << "NO" << endl;

}   

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: WRONG ANSWER

Test 4

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Test 5

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Test 6

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Test 7

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Test 8

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Test 9

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Test 10

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Test 11

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Test 12

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Test 13

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Test 14

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Test 15

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Test 16

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Test 17

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Test 18

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Test 19

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Test 20

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Test 21

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Test 22

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Test 23

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Test 24

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Test 25

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Test 26

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Test 27

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Test 28

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Test 29

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Test 30

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Test 31

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Test 32

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Test 33

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Test 34

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Test 35

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Test 36

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Test 38

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Test 39

Verdict: WRONG ANSWER

Test 40

Verdict: WRONG ANSWER

Test 41

Verdict: WRONG ANSWER

Test 42

Verdict: WRONG ANSWER

Test 43

Verdict: WRONG ANSWER

Test 44

Verdict: WRONG ANSWER

Test 45

Verdict: WRONG ANSWER

Test 46

Verdict: WRONG ANSWER

Test 47

Verdict: WRONG ANSWER

Test 48

Verdict: WRONG ANSWER

Test 49

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Test 50

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Test 51

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Test 52

Verdict: TIME LIMIT EXCEEDED

Test 53

Verdict: WRONG ANSWER

Test 54

Verdict: WRONG ANSWER

Test 55

Verdict: WRONG ANSWER

Test 56

Verdict: TIME LIMIT EXCEEDED

Test 57

Verdict: WRONG ANSWER

Test 58

Verdict: WRONG ANSWER

Test 59

Verdict: WRONG ANSWER

Test 60

Verdict: WRONG ANSWER

Test 61

Verdict: TIME LIMIT EXCEEDED