Building Teams

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define die(x) return cout << x << endl, 0
#define all(o) o.begin(), o.end()
#define endl '\n'
#define IOS ios::sync_with_stdio(0), cin.tie(0)
#define FILE freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout)
#define SZ(x) ((int)(x).size())
typedef long double ld;
typedef long long ll;
int gcd(int x,int y){ return (!y ? x : gcd(y, x%y)); }
int to_int(string sconvert){stringstream geek(sconvert);int xconvert = 0; geek >> xconvert; return xconvert;}
const int MAXN=200000+30,MAX_LOG=40,INF=1e18+10,MOD=1e9+7;
const double PI = acos(-1);
int mod(int x) { return (x % MOD + MOD) % MOD; }
int power(int x,int y){
    if(y==0)return 1;
    int c=power(x,y/2);
    c=(c*c)%MOD;
    if(y%2)c=(c*x)%MOD;
    return c;
}

int n, t;
vector<int> g[MAXN];
int visited[MAXN];
int color[MAXN];
int max_color = 1;
int is_impossible = 0;

vector<pair<int,int>> edges;
int dfs(int v, int root){
    visited[v]=1;

    int ones = 0;
    int twos = 0;
    int is_leaf = 1;
    for(int u:g[v]){
        // cout <<v<<"pp pp"<<u<<" " <<visited[u]<<endl;
        if(!visited[u]){
            is_leaf = 0;
            int c = dfs(u, root);
            if (c == 1) ones++;
            else twos ++;
        }
        else{
            int c = color [u];
            // cout <<c<<endl;
            if (c != 0){
                if (c == 1) ones++;
                else twos ++; 
            }
        }
    }

    if(is_leaf){
        // cout<<v<<" kk"<<g[v].size()<<endl;

        color[v] = 1;
        return 1;
    }

    // cout<<ones<<" "<<twos<<"--- "<<v<<endl;
    if (ones>0 && twos >0){
        is_impossible=1;
        return 1;
    }
    else if (ones>=0){
        color[v]=2;
        return 2;
    }
    else{
        color[v]=1;
        return 1;
    }
}


int MAIN(){
    int n, m;
    cin>>n>>m;

    for (int i = 0; i < m; ++i) {
        int a, b;
        cin >>a>>b;
        g[a].push_back(b);
        g[b].push_back(a);
    }

    for (int i = 1; i <= n; ++i) {
        if (color[i] != 0) continue;

        queue<int> q;
        color[i] = 1;
        q.push(i);

        while (!q.empty()) {
            int v = q.front();
            q.pop();

            for (int u : g[v]) {
                if (color[u] == 0) {
                    color[u] = 3 - color[v];
                    q.push(u);
                } else if (color[u] == color[v]) {
                    cout << "IMPOSSIBLE\n";
                    return 0;
                }
            }
        }
    }

    for (int i = 1; i <= n; ++i) {
        cout<<color[i] << (i == n ? '\n' : ' ');
    }

 

    
    return 0;
}
int32_t main(){
    IOS;
    int t=1;
    // cin>>t;
    while(t--)MAIN();
    return 0;
}

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