Building Teams

#include <iostream>
#include <vector>
using namespace std;

#define M (2 * (int)1e5 + 1)

int n, m;
vector<int> adj[M];
bool visited[M];

void dfs(int s) {
		if(visited[s]) return;
		visited[s] = true;
		int len = adj[s].size();
		for(int i = 0; i < len; ++i){
			dfs(adj[s][i]);
		}
}

int main(){
	cin >> n >> m;
	for(int i = 0; i < m; i++){
		int a, b;
		cin >> a >> b;
		adj[a].push_back(b);
		adj[b].push_back(a);
	}
	int foundTeam[M] = {0};
	for(int i = 1; i <= n; i++){
		if(!visited[i]){
			foundTeam[i] = 1;
			dfs(i);
		}
		else{
			if(foundTeam[i] != 0){
				cout << "IMPOSSIBLE";
				return 0;
			}
				foundTeam[i] = 2;
		}
	}
	for(int i = 1; i <= n; i++){
		cout<<foundTeam[i]<<" ";
	}
	return 0;
}

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: WRONG ANSWER

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: WRONG ANSWER