Astralis session I

input/code.cpp: In function 'int BFS(std::vector<std::vector<int> >&, std::vector<bool>&, int)':
input/code.cpp:23:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |         for(int i=0; i<roads[x].size(); i++){
      |                      ~^~~~~~~~~~~~~~~~
input/code.cpp: In function 'int main()':
input/code.cpp:42:28: warning: comparison of integer expressions of different signedness: 'unsigned int' and 'int' [-Wsign-compare]
   42 |     for(unsigned int i=0; i<(n-1); i++){
      |                           ~^~~~~~
input/code.cpp:54:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   54 |     for(int i=0; i< edges.size(); i++){
      |                  ~^~~~~~~~~~~~~~
input/code.cpp:81:23: warning: comparison of integer expressions of different signedn...

#include <iostream>
#include <vector>
#include <queue>


using namespace std;


int BFS(vector<vector<int>>& roads, vector<bool>& visited, int ini){
    queue<int> q;
 
    q.push(ini);
    int count = 0;
    
 
    while(not q.empty())
    {
        int x = q.front();
        visited[x]=true;
        count += 1;

        q.pop();
        for(int i=0; i<roads[x].size(); i++){
            if(roads[x][i]==true and not visited[i]){
                q.push(i);
            }
        }
    }

    //cout<<count<<endl;
    return count;
}


int main(){
    int n;
    cin >> n;
    vector<vector<int>> roads(n, vector<int>(n,false));

    vector<pair<int,int>> edges(n-1);
 
    for(unsigned int i=0; i<(n-1); i++){
        int a,b;
        cin >> a >> b;
        roads[a-1][b-1]=true;
        roads[b-1][a-1]=true;
        edges[i] = make_pair(a-1,b-1);
    }

    vector<bool> visited(n,false);

    bool sol=false;

    for(int i=0; i< edges.size(); i++){
        //cout<<i<<endl;
        int x = edges[i].first;
        int y = edges[i].second;

        roads[x][y]=false;
        roads[y][x]=false;

        visited = vector<bool>(n,false);

        int a = BFS(roads, visited, x);

        if(a == n/2){
            //cout<<"hola"<<endl;
            visited = vector<bool>(n,false);
            int b = BFS(roads, visited, x);
            if(b == n/2){
                sol = true;
                break;
            }
        }
        roads[x][y]=true;
        roads[y][x]=true;
    }

    if(sol){
        cout<<"Yes"<<endl;
        for(int i=0; i< visited.size(); i++){
            if(visited[i]==false){
                cout <<'M';
            }
            else cout << 'U';
        }
        //cout<<endl;
    }
    else cout << "No" << endl;

    

}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

Test 29

Verdict: ACCEPTED

Test 30

Verdict: ACCEPTED

Test 31

Verdict: ACCEPTED

Test 32

Verdict: ACCEPTED

Test 33

Verdict: ACCEPTED

Test 34

Verdict: ACCEPTED

Test 35

Verdict: ACCEPTED

Test 36

Verdict: ACCEPTED

Test 37

Verdict: ACCEPTED

Test 38

Verdict: ACCEPTED

Test 39

Verdict: ACCEPTED

Test 40

Verdict: ACCEPTED

Test 41

Verdict: ACCEPTED

Test 42

Verdict: ACCEPTED

Test 43

Verdict: TIME LIMIT EXCEEDED

Test 44

Verdict: TIME LIMIT EXCEEDED

Test 45

Verdict: TIME LIMIT EXCEEDED

Test 46

Verdict: ACCEPTED

Test 47

Verdict: ACCEPTED

Test 48

Verdict: TIME LIMIT EXCEEDED

Test 49

Verdict: ACCEPTED

Test 50

Verdict: ACCEPTED

Test 51

Verdict: ACCEPTED

Test 52

Verdict: RUNTIME ERROR

Test 53

Verdict: RUNTIME ERROR

Test 54

Verdict: RUNTIME ERROR

Test 55

Verdict: RUNTIME ERROR

Test 56

Verdict: RUNTIME ERROR

Test 57

Verdict: RUNTIME ERROR

Test 58

Verdict: RUNTIME ERROR

Test 59

Verdict: RUNTIME ERROR

Test 60

Verdict: RUNTIME ERROR

Test 61

Verdict: RUNTIME ERROR