Coloring

#include<bits/stdc++.h>
using namespace std;

#define MAXN int(1e6)
int n, m;
set<int> G[MAXN];

int deg[MAXN], col[MAXN];
set<int> pal[MAXN];

int main() {
    cin >> n >> m;

    for(int i = 0; i < m; ++i) {
        int a, b;
        cin >> a >> b;
        a--;
        b--;

        G[a].insert(b);
        G[b].insert(a);

        deg[a]++, deg[b]++;
    }

    priority_queue<pair<int,int>> Q;
    for(int i = 0; i < n; ++i) {
        Q.push({-deg[i], i});
        col[i] = -1;
        for(int j = 1; j <= 6; ++j) pal[i].insert(j);
    }

    while(!Q.empty()) {
        auto [w, v] = Q.top();
        Q.pop();
        if(col[v] != -1) continue;

        col[v] = *pal[v].begin();
 
        for(int u: G[v]) {
            G[u].erase(v);
            deg[u]--;
            Q.push({-deg[u], u});
            pal[u].erase(col[v]);
        }

    }

    for(int i = 0; i < n; ++i) cout << col[i] << " ";
}

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: WRONG ANSWER

Test 10

Verdict: WRONG ANSWER

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: WRONG ANSWER

Test 13

Verdict: WRONG ANSWER

Test 14

Verdict: WRONG ANSWER

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