The key to understanding this is

1. understanding BFS (breadth-first search)

2. understanding that binary, or any place system numbers, can be represented in a tree. For binary, each place represents two values, which can be represented as binary nodes in a tree:

                   "1"
   
                /           \
   
        "10"                 "11"
   
      /          \            /            \
   

   "100". "101". "110" "111

each node in the tree can make two new numbers, by adding a 0 and a 1, as shown above.

The BFS algorithm is

function bfs(root) {

    if (!root) return;



    const queue = new Queue();

    queue.enqueue(root);



    while (!queue.isEmpty()) {

      const node = queue.dequeue();



      // Process current node

      console.log(node.value);



      // Add all children to queue

      for (const child of node.children) {

        queue.enqueue(child);

      }

    }

  }

The core pattern is:

1. Start with root in queue

2. While queue not empty:

- Dequeue a node

- Process it

- Enqueue all its children

The queue ensures you process all nodes at depth 1, then all at depth 2, then depth 3, etc.