Algo - Simple DFS(Depth First Search) - V1.0

#include <bits/stdc++.h>
using namespace std;
#define d(x)                cout << #x << " = " << (x) << endl;
#define fr                  freopen("in.txt", "r", stdin);
#define fw                  freopen("out.txt", "w", stdout);
#define mem(x)              memset((x), 0, sizeof((x)));
#define pb                  push_back
#define LL                  long long
#define fastIO              ios_base::sync_with_stdio(false)
#define sf                  scanf
#define pf                  printf
#define sc1(x)              scanf("%d", &x)
#define sc2(x, y)           scanf("%d %d", &x, &y)
#define sc3(x, y, z)        scanf("%d %d %d", &x, &y, &z)
#define FOR(i, x, y)        for(int i=int(x); i<int(y); i++)
#define ROF(i, x, y)        for(int i=int(x-1); i>=int(y); i--)
#define all(c)              c.begin(), c.end()
#define unq(v)              sort(all(v)), (v).erase(unique(all(v)),v.end())
#define siz 1000000
#define MAX 100000

//Graph
vector<int> edge[MAX];
vector<int> cost[MAX];
//DFS visited node: colors: 0=white, 1=gray, 2=black
vector<int> visited(MAX);
//DFS validator
int max_depth = 0;

/////////////////DFS/////////////////////////
void DFS(int u){
    visited[u] = 1;
    for(int v = 0; v < edge[u].size(); v++){
        if(visited[edge[u][v]] == 0){
            DFS(edge[u][v]);
            max_depth++;
        }
    }
    visited[u] = 2;
}
////////////////////////////////////////////

int main(){
    fastIO;
    fw; fr;
    int n, e;
    cin >> n >> e;
    for(int i = 0; i < e; i++){
        int x, y;
        cin >> x >> y;
        edge[x].push_back(y);
        edge[y].push_back(x);
        cost[x].push_back(1);
        cost[y].push_back(1);
    }

    //printing graph
    for(int i = 1; i <= n; i++){
        cout << "Node: " << i << endl;
        cout << "Connected with: ";
        for(int j = 0; j < edge[i].size(); j++){
            cout << edge[i][j] << " ";
        }
        cout << endl;
    }

    //running DFSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSs
    DFS(1);
    d(max_depth);

    return 0;
}

//test case
/*
6 5
1 2
2 3
3 4
4 5
5 6
*/