[4%] (Continue Question 1) Build the compressed binary trie for the same seven 6-bit keys. For each branch node, define its bitNumber as the bit index used at that node to choose the left or right child. The leftmost bit is index 1 and the rightmost bit is index 6. Perform BFS starting from the root. When visiting a branch node, enqueue the left child before the right child. List the bitNumber of each visited branch node in BFS order.

Answer format: bitNum1, bitNum2, …