Graph - DFS and BFS

vector<int> adj[N];
bool visited[N];

void dfs(int s) {
  if (visited[s]) return;
  visited[s] = true;
  // process node s
  for (auto u: adj[s]) {
    dfs(u);
  }
}

queue<int> q;
bool visited[N];
int distance[N];

visited[x] = true;
distance[x] = 0;
q.push(x);
while (!q.empty()) {
  int s = q.front();
  q.pop();
  // process node s
  for (auto u : adj[s]) {
    if (visited[u]) continue;
    visited[u] = true;
    distance[u] = distance[s]+1;
    q.push(u);
  }
}