Breadth-First Search

1Queue<Integer> q = new ArrayDeque<>();2q.add(start); visited[start] = true;3while (!q.isEmpty()) {4  int node = q.poll();5  if (node == goal) return buildPath();6  for (int nb : neighbors(node))7    if (!visited[nb]) {8      visited[nb] = true; parent[nb] = node;9      q.add(nb);10    }11}