The Great Revegetation

    1#include <bits/stdc++.h>
    2using namespace std;
    3int main(){
    4    ios::sync_with_stdio(0);
    5    cin.tie(0);
    6    int n, m; cin >> n >> m;
    7    vector<int> node(n + 1, -1);
    8    vector<vector<int>> adj(n + 1);
    9    for(int i = 0; i < m; i++){
    10        int a, b; cin >> a >> b;
    11        adj[a].push_back(b);
    12        adj[b].push_back(a);
    13    }
    14    for(int i = 1; i <= n; i++){
    15        vector<bool> used(5);
    16        for(int c : adj[i]){
    17            if(node[c] != -1){
    18                used[node[c]] = 1;
    19            }
    20        }
    21        for(int j = 1; j <= 4; j++){
    22            if(!used[j]){
    23                node[i] = j;
    24                break;
    25            }
    26        }
    27    }
    28    for(int i = 1; i <= n; i++){
    29        cout << node[i] << (i == n ? "\n" : "");
    30    }
    31    return 0;
    32}