Untitled

#include <iostream>
#include <vector>
#include <queue>
using namespace std;
const int MAXN = 1005;

int v, e;
vector<int> adj[MAXN];
int parent[MAXN];
bool visited[MAXN];

void addEdge(int u, int v) {
  adj[u].push_back(v);
}
void BFS(int source) {
  queue<int> q; // queue for storing vertices in BFS order

  // mark source vertex as visited and enqueue it
  visited[source] = true;
  q.push(source);
  parent[source] = -1; // source vertex has no parent

  while (!q.empty()) {
    int u = q.front();
    q.pop();

    // iterate through all the vertices adjacent to u
    for (int i = 0; i < adj[u].size(); i++) {
      int v = adj[u][i];
      // if vertex v is not visited before, mark it visited and enqueue it
      if (!visited[v]) {
        visited[v] = true;
        q.push(v);
        parent[v] = u; // set parent of v as u
      }
    }
  }
}

int main() {
  cin >> v >> e;

  // add edges
  for (int i = 0; i < e; i++) {
    int u, v;
    cin >> u >> v;
    addEdge(u, v);
  }

  BFS(0); // start BFS from vertex 0

  for (int i = 0; i < v; i++) {
    cout << "Vertex " << i << " has parent " << parent[i] << endl;
  }

  return 0;
}