BUGLIFE - A Bug’s Life

#include <bits/stdc++.h>
using namespace std;
#define max 100000
vector<int> graph[max];
vector<int> visited;
int color[max];

void dfs(int n) {
    visited[n] = true;

    for (int i : graph[n]) {
        if (color[n] == 0) {
            color[i] = 1;
        } else if (color[n] == 1) {
            color[i] = 0;
        }

        if (!visited[i]) {
            dfs(i);
        }
    }
}

int main() {
    int t, v, e, count(1);
    int a, b;
    cin >> t;
    while (t--) {
        cin >> v >> e;
        visited.assign(v + 3, false);
        bool bicolorable = true;
        memset(color, 0, sizeof(color));

        for(int i = 0; i < v + 3; i++) {
            graph[i].clear();
        }

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

        dfs(a);

        int c;
        for (int i = 0; i < v + 3; i++) {
            if (graph[i].size() > 0) {
                c = color[i];
                for (int j = 0; j < graph[i].size(); j++) {
                    if (c == graph[i][j]) {
                        bicolorable = false;
                        break;
                    }
                }
            }

            if (!bicolorable) {
                break;
            }
        }

        printf("Scenario #%d:\n",count++);
        if(bicolorable) printf("No suspicious bugs found!\n");
        else printf("Suspicious bugs found!\n");
    }
}