find cycle in undir graph(graph paint algo)

#include<bits/stdc++.h>
using namespace std;
const int NMAX = 1e5 + 3;
int n, m;
vector<int> graph[NMAX];
enum States {
    UNVIS,
    INSIDE,
    EXITED
};
int daddy[NMAX];
States nstate[NMAX];
pair<int, int> cycleLim(-1, -1);

void read() {
    cin >> n >> m;
    assert(n > 0 && n < NMAX);
    for (int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        assert(a >= 0 && a < n && b >= 0 && b < n);
        graph[a].push_back(b);
        graph[b].push_back(a);
    }
}

bool dfs(int node, int daddy) {
    nstate[node] = INSIDE;
    for (auto it : graph[node]) {
        if (it == daddy)
            continue;
        if (!nstate[it]) {
            ::daddy[it] = node;
            if (dfs(it, ::daddy[it]))
                return true;
        } else if (nstate[it] == INSIDE) {
            cycleLim = make_pair(it, node);
            return true;
        }
    }
    nstate[node] = EXITED;
    return false;
}

void findCycle() {
    fill(daddy, daddy + NMAX, -1);
    fill(nstate, nstate + NMAX, UNVIS);
    for (int i = 0; i < n; i++)
        if (!nstate[i] && dfs(i, daddy[i]))
            break;
    if (cycleLim.first == -1) {
        puts("acyclic");
        return;
    }
    vector<int> cycle = {cycleLim.first};
    for (int i = cycleLim.second; i != cycleLim.first; i = daddy[i])
        cycle.push_back(i);
    cycle.push_back(cycleLim.first);
    reverse(cycle.begin(), cycle.end());
    for (size_t i = 0; i < cycle.size(); i++) {
        cout << cycle[i];
        if (i != cycle.size() - 1)
            cout << "->";
    }//*/
}

int main () {
    read();
    findCycle();
    return 0;
}